Ability to DIY and time taken are certainly considerations. My other half is semi relaxed as long as progress is happening.
My kitchen refit took 6 months. From the moment we had the new one delivered to the moment "er indoors" signed off the works as complete.
I did it all, apart from fitting the quartz. That added a bit to the timeline but not that much. Covid year so I had to wait at one point for them to start the visits again (templating)
I could probably have halved the timeline in reality had I of gone for it a bit more hardcore, but I have an allotment and that also takes time.
I started late March 20 and finished Sept 20.
Bathroom was more like 9 months but I spent the first 3-4 basically wasting my time, trying to get tiles off plasterboard that had never been painted or sealed. Eventually I just went for removal (heavy lump hammer) and reboarded. If I was doing it again now from scratch I would just do that from the start.
Again half the time would have been possible.
One of the things we did with both was an evolution approach we we know basically what we want, but we adapt as we go. So some stuff like colours and exact fittings we decide when we get to the point they are needed.
My kitchen more than one trade has commented on and one was open mouthed that it was fitted by an accountant.
One said thats really nice floor tiling. The other said you cheeky bugger he may turn around and say hes been a tiler for 20 years. It was at that point I said I was an accountant
The first jobs i did were break even, as I bought tools as we went. Later on you have most of what you need. I do try to practically stick to one new tool per job.
Some tools will pay for themselves in one job, diamond tile cutter, that sort of thing. Some tools you find out afterwards just how useful they are, multitool for example.
There is 100% more satisfaction and as long as your not a bodger for many jobs you will have a better quality than trades doing it. Its where the time angle is a benefit not a penalty.