You should check your tires for wear at least once a month and before and after long trips. To determine whether you need to
(a) buy new tires,
(b) have your wheels balanced,
(c) have your wheels aligned, or
(d) change your driving habits, simply read your tire treads for clues

1) Clue: Both edges worn

Culprit: Underinflation

Remedy: Add more air; check for leaks

2) Clue: Center treads worn

Culprit: Overinflation

Remedy: Let air out to manufacturer's specifications

3) Clue: One-sided wear

Culprit: Poor alignment

Remedy: Have wheels aligned

4) Clue: Treads worn unevenly, with bald spots, cups, or scallops

Culprit: Wheel imbalance and/or poor alignment

Remedy: Have wheels balanced and aligned

5) Clue: Erratically spaced bald spots

Culprit: Wheel imbalance or worn shocks

Remedy: Have wheels balanced or replace shocks

6) Clue: Edges of front tires only worn

Culprit: Taking curves too fast

Remedy: Slow down!

7) Clue: Saw-toothed wearpattern

Culprit: Poor alignment

Remedy: Have wheels aligned

Clue: Whining, thumping, and other weird noises

Culprit: Poor alignment, worn tires or shocks

Remedy: Have wheels aligned or buy new tires or shocks

9) Clue: Squealing on curves

Culprit: Poor alignment or under-inflation

Remedy: Check wear on treads and act according

Source: http://carworldng..com.ng/2016/01/car-tips-checking-your-tires-for-wear.html