>Even something as straightforward as painting a wall will be hard when you are doing it for the first time.

Painting is one of the things I do myself, in part because it's something I do often enough that I more or less know the various gotchas, techniques, etc. It's also the case that, when redoing areas that were already painted which is most of what I do these days, I can take some very timesaving shortcuts that someone I hire can't. I can repaint a ceiling without bothering with meticulously masking all the edges and corners. If I don't repaint 100% of the area it probably doesn't matter unless things are in really bad shape.