Maybe this is a normal thing and I am worrying for no reason, but two flat tyres in one week is a new record for me. I drive a 2018 Nissan Sunny for a ride service in the evenings, so the car does about 250 kilometers a day, mostly on roads near the industrial areas where there is always some sand, stones and bits of metal. Monday the rear right tyre went soft overnight, and I got it fixed. Then on Friday morning the front left was low again. The car has about 140,000 kilometers, and I think the tyres are original or close to it. A fellow driver told me old tyres get thin and pick up nails much easier, so I should just change all four and stop wasting time. Another driver says it is only bad luck and the roads here are full of rubbish, and that changing tyres early is a waste for someone who needs every dirham. I read a page from a workshop in Sharjah about tyre problems, and it explained that a flat is not always a nail, because a bad valve, a bent rim edge or a slow leak around the bead can also let the air out, and that a proper check means looking inside the tyre, not only on the outside. That made me think the second flat might not be a new puncture at all. Since I stop near Al Qusais between rides, I typed Quick tyre change for flat tyres near Al Qusais Industrial Area into my phone, mostly to see if they can look at the problem fast, because every hour in the shop is money I lose. So here is what I want to ask. How do you tell if a tyre is too old or worn to keep patching, is there a number or mark I can check myself? Do shops put the tyre in water to find a slow leak, and should I ask for that? Also, is it better to change two tyres at the same axle or all four at once? One more thing, how many patches are too many on one tyre before it becomes unsafe for a car that drives all day? If you drive a lot for work, please tell me how long your tyres last and what you pay. Thanks everyone.