Even when working with a highly rated computer repair shop, it’s still important to deal with it carefully.

Put the problem in writing.

Give the shop a written description of your computer’s issues. Describe the occasions when problems occur, exactly what happens, etc. Put this information in writing—otherwise the shop may forget what you’ve said by the time it starts working on your computer.

If possible, talk to the technician.

As with most types of repairs, it’s preferable to speak directly with the person who does the work. With a face-to-face exchange, you can make sure you adequately communicate the symptoms. Also, personal contact may make the technician care more about doing the job right. And you may be more understanding when the technician can’t solve a problem after you’ve had a chance to discuss the obstacles.

Insist on a written estimate.

Unless the shop demands that you authorize repairs up to a certain dollar amount, request a written estimate upfront.

To protect yourself from a big price surprise, tell the shop that no repairs are to be made without a written estimate and without your approval. If you accept an estimate, state in writing that you will not pay for charges that exceed the estimate by more than 20 percent.

New Jersey law gives you the right to obtain a written itemized estimate, and most shops in Delaware and Pennsylvania are willing to give you one if you ask. New Jersey law also dictates that, unless you authorize a higher figure, charges must not exceed your estimate.

Consider whether the repair is worth it.

Repairing a computer often costs hundreds of dollars. If you have a newer device and are satisfied with its capabilities, spending that much makes sense. But if you have an old computer that will soon become obsolete, think about whether you might be better off applying repair costs toward a new model.

If you are quoted a high price, get more estimates.

Although it can be difficult to get estimates for repairs, most shops will provide them if you need only upgrade services. Contact a few and describe the upgrade or repairs another shop has recommended. If you are shopping for repairs, of course, this process doesn’t tell you whether the first shop’s diagnosis or recommendations are correct. If you suspect that they are incorrect, consider taking your device to a second shop for an estimate—even if it costs you an estimate fee.

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Nail down the time.

Although unforeseen problems can arise, you’ll be in a better position to argue for priority service if you’ve received an advance commitment as to when the work will be completed.

Ask for replaced parts.

Even if you’ve never seen a motherboard or hard drive, shops don’t know how much you—or your nerd brother-in-law—knows. The shop will be reluctant to replace good parts or claim falsely to have replaced parts if it knows it has to return replaced parts to you.

If you leave a device with a repair company, get a receipt.

Get a detailed invoice.

The invoice should state: name and address of repair shop; your name and address; description of repair; itemized charges; date repair was completed; and statement of any warranty. An invoice will be essential if you need to take advantage of the shop’s repair warranty.

Pay by credit card.

If you are dissatisfied with the work and the company is unwilling to make things right, you’ll have the option to contest the charge with your credit card company and get your money back.

Ask whether there’s something you can do (or stop doing) to prevent future problems.

Test the device as soon as you get it home.

If the problems persist, either take the device back to the shop immediately or email the shop to document that the problems were never solved.