Been there done that and it wasn't that bad. We didn't spend any money on the house beforehand or whilst we lived there.

At the time i was building our castle and only went there to sleep. My wife who had been abroad for over 10 years enjoyed spending time with her elderly parents. My in laws had a pension and never asked or expected us to pay for anything. Not all families are the same though.

Both have since passed away and i miss them.

It really depends on the in laws and how comfortable you around them. Am guessing i might be the only one in the yes camp.