When we had no money and I used to do stuff like fit bathrooms and kitchens in our house.
A while back we asked a plumber friend (professional, qualified, full time business) to replace a couple of taps and a waste in our bathroom sink unit, which we wished to keep. However the taps were old and the fittings holding everything together were a bit corroded and reluctant to come undone with everything in situ - he had a go, but couldn't shift joints & suggested we had a nice vanity unit fitted instead.
The answer was 'obvious' old skool - just take the unit off the wall to get better access to joints and where they wouldn't cooperate then apply brute force or a hacksaw.
To a 57 year old who hasn't done any plumbing work to speak of in more than 10 years, it took an hour to get everything off the wall and in bits - not really any touble at all - but then 2 hours to get it all back and leakfree (it all had to come apart again because the new waste leaked - seems OK now) which was annoying and a sign that I really am out of practice.
In a way I'm pleased that I can still do this stuff, but I'd have preferred him to have done it first time & just taken an extra hour over it. And I have a headache, just like I used to get from doing this stuff. There's something about mechanics that requires just as much mental agility as designing tests to measure billionths of a gram of protein, and those cranial demands make themselves felt.