Those of us who are of a certain age remember when the purchase of a big television set also cost you a couple of six-packs — to pay off the friends needed to help muscle it into position. These days, new TV screens are not only lighter, they’re flat. You can hang them on your wall like artwork.

The hidden cost of doing so is the hanging apparatus. Basic low-profile mounts can be purchased for less than $100, while full-motion versions start at that price and can cost $300 or more. Consider that when estimating your TV purchase budget.

Hanging a television on your wall isn’t as simple as hanging a picture, but it’s close. Think of it as a big, heavy, ungainly picture that you might want to tilt, swing and rotate.

There are essentially two things to consider when wall-mounting a TV: how and where.

THE HOW

This is straightforward engineering. First, you choose the correct hanging apparatus to suit your needs. These range from a simple fixed mounting, like a picture frame, to a version that tilts forward to improve picture quality, to fancier "full-motion" gizmos that allow the TV to be arranged at different angles, tilts and distances, and all without the help of your six-pack-guzzling friends.

When shopping for a mount, note they’re not really rated by weight, but by picture size. Remember that picture size is measured diagonally, corner to corner.

All flat-screen TVs have mounting holes in the back, although they might be covered with plastic caps that must be pried off. They are arranged in a square or rectangle, in a size determined by something called the VESA (Video Electronics Standards Association) code, which tells you how far apart the holes are in millimeters. Your TV manual or the shipping box will reveal the VESA code for your TV.

For example, if your set is "VESA 60," that means the mounting holes are 60 millimeters apart on each side. If the code is something like "VESA 75/150," that means the mounting grid is a rectangle with those dimensions.

Most wall mounts are compatible within a range of VESA sizes or can be adjusted. Most also have two pieces, the part that attaches to the wall, and a rack that securely bolts to the back of the TV. Once each piece is installed, they just click together. That’s in most cases, but there are dozens of mount designs.

Follow the mount instructions and assemble the back rack, then bolt it to the TV. If your TV comes with a stand, take it off.

Audiovisual pros prefer to bolt the back racks on with the TV leaning upright, but if you must place it face down, do so atop a blanket or bed so the screen won’t get scratched. It’s also a good idea to attach the various wires at this time, because the jacks are easier to get at.

"If your TV is going to be flat-mounted, make sure the cable connection doesn’t stick straight out of the back of the TV and prevent that," suggested Cheryl Smith of At Home Theater of Hawaii at Honolulu Design Center.

The back bracket might also have some wiggle design so that the attachment point can be adjusted. The ideal attachment point is slightly above the center of the TV set so that the weight of it hangs vertically instead of pivoting.

The wall mount portion needs to be securely — repeat, securely — attached to the wall. That means long lag bolts going into wooden studs at the very least, and in the case of a larger TV, to at least a pair of wall studs. Walls with metal studs won’t hold the weight, and drywall anchors will rip right out.

Older Hawaii houses with thin walls might need external beefing up. Concrete, brick or cement-block walls are going to need stout anchors from the hardware store.

"Exterior walls can take a load better," explained Richard Reese of Cine Systems on Piikoi Street. "On the other hand, if you’re living in a condo, the exterior walls and ceiling are prestressed concrete, and rules generally prohibit drilling into common areas or load-bearing walls."

Securely. Got that? The many little overlooked microscopic vibrations all day long that rattle a TV on a wall gradually eat away at the tautness of the mounting fixture.

"Always, always mount the plate into wall studs and never into drywall," said Smith. "It’s a big no-no."

She also pointed out that articulating arms that project the TV out away from the wall can act as a lever, further stressing the wall mount.

Another concern, particularly for condo owners, is sound transmission, noted Reese. A TV bolted to a common wall can send sound vibrations right through the wall into your neighbor’s living space.

How will you handle the cables attached to the back of the TV? Some people are content to simply let them hang, while others gather them behind an electronics "raceway" covering that hide the wires. For a neater installation, you can also feed them through the wall behind the TV and then down and out a wall box, a junction or "j-box" rather like an electrical outlet. This requires more work and might demand cutting into firebreak stud crosspieces.

The TV power cable is something else, and isn’t rated to be dangled inside a wall. An electrician might be able to install an additional electrical outlet up behind the TV.

When the time comes to hang your TV, get a friend, so this costs you only one six-pack. Although flat-screen TVs are heavy, they’re not THAT heavy, but they are awkward and fragile. It’s just easier with two people. Snap it into place on the mount, and adjust the level of your TV with — what else? — a level.

THE WHERE

Like the real-estate people say, it’s all about location, location, location.

First, there are practical concerns.

"The ideal choice is always above the cable-box outlet," said Smith. "It simplifies things. There are people who hide all their electronic devices in one closet and run R/F or coaxial cable all over the house, but most people mount their TVs at or near the cable outlet."

"Much depends on how you use your TV," explained Reese. "Do you want it as a movie experience or more as a companion thing, where the TV is on to keep you company and informed while you’re in the room? They’re even filmed differently. Movies have small details, and TV shows have lots of close-ups. For movies you sit closer; for TV you can be farther away. Most people balance the two."

"Eye level is best, from wherever you like to sit," said Smith. "If it’s up too high, it can be fatiguing on your neck. Over the fireplace, ridiculous. How big the TV is a personal preference — some people sit in the front row of a movie theater; others sit in back."

Go to a store that has various sizes of flat-screen TVs, stand in front of them and move back and forth until the size "feels" right, then note the distance to the TV and screen size.

"A big room with a tiny TV up high can be as wrong as a TV that’s too big in a small room," said Smith. "Also, keep in mind that many homes now have a great room that is open to the kitchen, and people like to be able to see and hear the TV from the kitchen."

So, size matters. Screen resolution, not so much, because most TVs sold these days are high-resolution, which means you can sit nearer to them without eyestrain.

"An articulating arm means that your screen can be viewable from many different angles," said Reese. "It can be adjusted for personal preference or privacy, or just to eliminate glare from windows."

Movie theaters angle for a screen that takes up roughly 30 degrees of your field of view. If you make a 30-degree cardboard triangle, sit in your favorite chair, hold the triangle point up to your eye and sight down the sides, you’ll be able to estimate an ideal size for your TV.

Some home-theater designers use a simpler rule of thumb, the "2-to-5 Principle," which estimates that the viewer should sit no closer than two times the width of the screen nor farther away than five times the width of the screen. This is only an approximation, mind you. For the fine detail in high-definition TV screens, it’s more like a 1.5-to-3 ratio.

How low should you go? There’s one school of thought that thinks high-definition flat screens are like works of art and should be hung like framed pictures, with the center at eye level while standing up.

Few people watch TV standing up, but centering the screen at eye level for sitting viewers seems too low. A better height places the bottom third of the screen at eye level. And, if you’re leaning back in a recliner, do your toes obscure the screen?

SO, HANGING a TV isn’t quite like hanging a picture, although it all comes down to whether the mounting "feels" right to you. The price of hiring professionals to wall-mount your TV can be several hundred dollars.

"The price of such wall mounts are pretty reasonable," said Reese, considering what they do, and buyers need to factor the cost in their budgets.

"But the price of high-definition screens has dropped enough. Used to be, what might have been the ideal TV for you was simply unaffordable. Now it is. Just don’t scrimp on the mounting system or your TV might wind up on the floor.

"Make sure you follow the instructions. Television mounting systems are made by people who know what they’re doing," said Reese. "But they’re not always installed by people who know what they’re doing."