What's some renovation you regret having and some that's actually worth the money?

Good quality composite decking is a thousand times better than wooden decking. Doesn't grow mould and get slippy, doesn't need to be sanded down and painted/oil applied every year or two and is super easy to clean. Another worthwhile renovation is actually making sure you have plug sockets where you need them or may want them in the future. Even if they go unused for a while, they're rarely an eyesore and having more, not less is always better. As for kitchens, dont have the work done through a company. They'll tear you a new one. Go to a local kitchen supplier, pretend you're interested in what they're selling but also ask if they know any local kitchen fitters, you'll get a much better deal and usually a better finish because lots of companies, unless you're spending mega money, will 'rush' to get the job done. Same thing for bathrooms. We buy supplies from a company that have their own fitters, but we are a hell of a lot cheaper when it comes to labour costs. And again, the same thing for windows and doors. I know someone who used a well known company to get 4 windows at the back of their house replaced. The windows aren't anything special, they're not huge, or fancy. They paid £6,000 for 4 windows supplied and fitted. The same windows, when bought from an independent frame maker would be no more than £1500 and fitting them and siliconing takes a day, so you're talking like £2500 from an independent fitter. Don't let companies screw you over.