Coffee.
I blame James Hoffman entirely.
Within a year I went from:
Drinking instant coffee at home, but really enjoying “proper coffee”
To
Buying a cafetiere (~£15) + preground coffee
To
Buying a Nespresso (~£60 on offer) + pods
To
Buying a budget espresso machine (~£120) + preground coffee
To
Wasting my money on a cheap manual coffee grinder (~£50) + beans
To
Immediately replacing it with an entry level Sage grinder (~£170)
To
Buying an entry Level “proper” espresso machine (~£700)
It took me a good 2-3 weeks of practicing and dialling in before pulling a good shot of coffee that I’d actually want to drink, but by that point it was also about learning a new skill, learning how different aspects of the process affect the end result and learning how to make all sorts of different espresso-based drinks.
My girlfriend thought I was nuts at first, but a year or so later even she agrees it was worth the investment. I still for the life of me can’t get the hang of latte art though.
The problem is now though that I’m a waaaay more critical of coffee from coffee shops, because I spent a long time making bad coffee whilst learning!
Then in a lot of places (check your local tenancy laws to be sure), you’re legally allowed to get someone in yourself to do it (or do it yourself) and deduct the expense from rent payment.