Tyres are a very important part of a vehicle and it you fall victim to a flat tyre or worn tyre then you will know how badly it can affect the drivability of the car. Most car owners have come across a deflated tyre at some point in there driving years. It may be that you have driven over something in the road and had to pull over as it has instantly puncture it, or it may be that you have =had a slow puncture and notice that over the course of a few days or a week, it has gotten worse.
If you have even a slow puncture, it is worth taking it to a garage as soon as possible, they will be able to remove the tyre for you and check where the air is leaking from. Many punctures can be repaired which usually costs around £10-£20 per repair and it is always worth asking prior to getting a new tyre. Sometimes it may not be that the tyre is punctured but that the beading has gone around the tyre wall. It could also be an issue with the wheels not sealing properly against the wheel to make an airtight seal. Either of these issues may require the wheel to be repaired or you having to buy a new wheel which can be costly especially if you have alloys.