If I had a 5 year old Polo GTi and enjoyed driving it I'd just get it serviced, ensure by breakdown insurance was up to date and drive the wheels off it. It's not going to break. It's less likely to break now than it was when it was new because the "it's been wrongly assembled or with dud parts" faults have been fixed. What mileage has it, 50k? You can double that without incident if you keep the servicing up to date. If it needs a tidy up and a bit of paint here and there, have it done. It's a couple of tanks of fuel. Around 10 years/100k you can expect brake discs all round and possibly a clutch, and the service and MoT will be flagging up suspension bushes etc. But all that stuff is for dirt cheap. Between 50 and 100k most cars these days don't need anything beyond service. It's a sweet spot and one I'd like to stay in except that I'm too tight and I just keep the things after 100k and pay the occasional bill.