It is recommended to check your tyres very frequently. It can be stated, that you can’t check them often enough. The question remains how often should they be checked. I would say that when you stop at the petrol station to fill up your car, then should try to check the tyres. Petrol stations tend to be well lit and you have the necessary equipment there to care for the tyres, if there are any problems.

Do a quick visual check for any bulging of the tyre, and defects on the sidewall and check the tread depth. This can be done very quickly. Often tears or bulges come from hitting the curb while trying to park your car. So be careful when you park your car.
Check the air pressure in the tyres and top up with air if needed. The correct pressure ensures that you get the best performance from your tyres. It also reduces the rolling resistance, which saves you money on petrol. You will also have even wear and the tyres will last longer. Safety aspects are also improved as you will have shorter braking distance and better control over your car while driving. When driving on wet roads it is important that your tyres are able to push away sufficient amount of water to avoid aquaplaning.