Before you drive the car away from the shop, ask the shop for a guarantee. You are likely to get a minimum of 30 days’ guarantee against defects in parts, materials, and workmanship, and most high-quality shops offer guarantees of six months or longer; the length of some guarantees varies by type of job. Whatever guarantee you get, get it in writing.

When the shop tells you your car is ready, inspect it carefully—by eye and by touch. Look most closely at:

Dent and Rust Removal

There’s more than one way to fix a dent. A good shop will remove a dent by leaving a nearly smooth surface and applying only a thin skin of plastic filler to completely even it out. Poor shops will fill in dents with a lot of plastic filler. Although the filler hardens and can be smoothed out to look like metal after being painted, the hardened plastic is brittle and may fall out or crack after another impact. Also, thick plastic patches tend to form webs of hairline cracks, which show through the paint after a few years.

Good shops also carefully remove all rust before patching rust spots. A little remaining rust will spread rapidly.

While it’s hard to tell how a shop did its dent and rust spot repairs, you will be able to tell whether the shop did careful work. Examine repaired areas closely by eye and hand. If you find uneven spots, tell them to redo the work.

Corrosion Protection

Welding, cutting, and grinding galvanized steel can remove its protective coating, leaving the area susceptible to corrosion. Shops should re-treat these areas with a protective coating before painting. Depending on what work the shop needs to perform, it should apply an etch primer, epoxy primer, or weld-through primer before painting the area.

Although this is a job some shops try to skimp on, quality shops will do it the right way. The problem is that once your car is painted, you won’t be able to tell if the corrosion protection was applied correctly. One strategy? Make sure paintwork is covered by a manufacturer’s lifetime warranty. All major paint manufacturers provide lifetime product warranties; if a shop has failed to properly apply corrosion protection and the area begins to rust, the warranty will let you redo the work at a shop of your choice.

Painting

It’s easy to spot most paint problems. If paint is sprayed on too thickly, or if the mixture used is not right for the temperature of the spray booth, the paint may drip or sag or have an orange peel-like texture. On the other hand, if paint is applied too thinly, it may not have enough gloss. If dust is not properly controlled, it will show up in the paint surface.

The toughest problem for painters is matching colors, with metallic and pearl colors especially difficult to match. While you can’t expect a perfect match on an old car, on newer cars it should be very close. Good painters mix paints using a manufacturer’s formula, then tinker with the color if it isn’t quite right. They also merge the new color with the original by spraying lightly over portions of old paint adjacent to newly painted panels.

If you are not satisfied with a paint job, insist that the shop do it again. But be aware that perfection may not be possible and that repainting is expensive and time-consuming.

Drivability

Take a test drive if the damage was substantial. The car should function as it did before the accident. Check especially that wheels are properly aligned—that the car doesn’t pull to one side of the road or the other.

Verify that every feature of the car works as it did before the repairs—door handles, trunk lid, hood, windows, even the sound system and windshield wipers—before leaving the shop.