Any time you're making improvements on your house -- whether you're adding a whole new wing or rejuvenating a bathroom -- the project will go more smoothly if you feel comfortable dealing with the contractors who do the work.

Especially if construction is strange to you, the key is to let the contractors give you an education. The first plumber who bids on the job may overwhelm you with technical terms, but by the time you get to the third, you'll have a good idea how many hours of work are involved in your job, what a T-trap is, and how much to play for labor.

Don't insist on a contract. The term "contractor" is misleading since many jobs -- such as plumbing, masonry, excavation -- are commonly billed on some other basis entirely. Plumbers usually charge for time plus materials. Masons may ask for so much per brick or block. Excavators work by the hour, plus a moving - in fee for getting the equipment there.

It's tempting to want a contract so you'll know what your exact costs will be, but unless the contractor likes to work this way, don't be stubborn. A reluctantly drawn contract may be so padded that the work will cost you more than it would have paid for in the usual way.

If materials are involved, figure whether it will be more to your advantage to buy them directly or through the contractor. You can get fixtures through your electrician, keeping in mind that he makes money on each one you buy, or you can purchase them yourself. Since the electrician probably gets better discounts than you can, it may be cheaper to let him do the buying.

Does hiring a licensed contractor help you? In jurisdictions where licenses are required, all legitimate professioals will have them. Keep in mind, however, that a license may be, in effect, only a tax the contractor pays in order to do business.

Even if he has to pass a test to get (See CONTRACTING, E22) (CONTRACTING, From E1) it, the license does not serve primarily as a consumer protection measure. It helps eliminate outright fraud, but it doesn't assure you of either low costs or quality workmanship.

Your best policy is to hire by both price and reputation. Since contracting is a clientele business, it's fairly easy to find out which plumber will quote low hourly rates but then take longer to do the job, or which excavator has a reputation for not appearing on schedule.

Check with a broad range of suppliers and other clients with whom the contractor has done business. This is important. No contractor pleases everyone, so the fact that one person tells you the work is bad may not mean much. Get an overview of opinions before you choose.

Whenever possible, look at other work the contractor has done. In most areas, structural soundness is controlled by local building codes. All you have to worry about is aesthetics. Masonry, drywall, carpentry, and paving work tell their own stories.

Once you've made your choice, it's important to know how much direct supervision is required. If you're paying by the hour, of course you'll have to keep track of the time. Otherwise, a minimum of intervention may be best. A mason is likely to be annoyed rather than flattered if you linger at the job site peering into the mortar mix. You probably don't know much about what he's up to, and besides, you're paying by the brick. He's only going to think you don't trust him.

When you do complain, be sure you have a legitimate gripe. Some work -- carpentry and drywall in particular -- looks appalling until it's complete. That doesn't always mean it's being done incorrectly. Unless you really know what you're talking about, check illustrated building manuals or ask questions and weigh the answers before you go on the offensive.

Sometimes you'll feel that workers are loafing. Here you have a genuine grievance if you're paying by the hour. Just remember that the contractor is in charge of his workers. You aren't. Tell the contractor and let him do the reprimanding.

What about delays? The paving contractor may say he'll do your driveway on Tuesday and then not show up for weeks. Unfortunately, the very nature of contracting makes some delays inevitable. A contractor is always bidding for more jobs than he can handle at once, on the assumption that he will get only some of them. If he gets them all, some will have to be put off.

You, alas, are probably high on the list of put - offs. Many contractors also work for builders who give them many jobs each year. Given a choice they will go to the builders first. They'll also do big - money jobs more quickly than small ones. If you're replacing your kitchen cabinets and someone else is building an addition, be prepared to wait.

The only thing you can do, short of working in the contractor's off - season, is to become the squeaky wheel on the carriage. If you call the carpenter frequently, leave messages, perhaps visit his job and ask when he's planning to do yours, eventually your sheer nuisance value may pay off. The carpenter will do your work and put off a less vocal client. The key here is to remain polite no matter what. Nastiness, threats and anger may keep him away indefinitely.