Like cambelts, timing chains don’t last forever. Over time, the chain can stretch causing it to skip a gear on the cam or crankshaft. This can cause the engine to misfire, lack power or just run badly. Other signs could be small bits of metal in the oil (although that can be other things as well), a rattle in the engine or the check engine light introducing itself to you. If you ignore these signs and the chain breaks while you’re driving, replacing the chain itself may well be the least of your worries; valves, pistons and other components can be badly compromised. A good mechanic will pick up any warning signs. The fact is 1/ for as long as you own a vehicle, there will always be a cost of maintaining it and 2/ regular servicing and preventative maintenance is a good investment; the cost of that will always be less than the cost of fixing it when it breaks. There are no shortcuts. The plus side is that a well looked after car with a good service history is worth more when you go to sell it. So, it’s not all cost