Apart from the initial outlay of buying an RO, where is the faff?
Assuming you have room in a garage it’s no more faff than using DI only. I have a static setup and literally switch a valve and am producing water from 380 to 004 within seconds.
I’ve saved £240 in resin in 6 months since using an RO. Long term using an RO (water at 380) will work out far more cost effective than when I was using DI with water at 070.
I haven’t got a garage mate, that’s the problem for me.
So space, frost protection, water bill, filter changes etc etc, became a faff.
Also I live in an area that has extremely hard water, so it wasn’t fun. Much easier for me to buy from my mate, it works out cheaper as he’s not on a water meter, so sells me 750litres for £10!
Appreciate if you have a garage, then it’s not too much of an issue.