We're older now, but did three mainly DIY renovation projects starting when DS was six weeks old. He'd just turned eight when we moved into the third. I was running my own business (a shop for which I designed some stock myself) and OH was employed in the interior design industry.
The first (3 bed, 3 reception mid terrace Victorian) really just needed a new kitchen and redecoration throughout. The second (4 bed, 3 reception, 2 bath Victorian detached) needed a rewire and new heating system (professionals did these), new kitchen, two new bathrooms and redecoration.
The third (6 beds, 3 receptions, 3 bathrooms, detached Victorian) was considerably larger at 3500 sq ft and was configured as several flats when we bought it. Everything needed doing including removing partition and load-bearing walls, rebuilding the original staircase and gothic style conservatory, plus replastering where necessary. OH did the plastering etc and we removed walls ourselves (having obtained structural engineer calculations etc). Windows, heating, rewire done by the pros.
Looking back I honestly don't know how we did it whilst both working and with a young DS, but we'd come home, eat, get him to bed then start demolition/decorating. House 3 took around eight years to complete which, imo, most people wouldn't accept - I recall one friend asking if we were planning to move into a hotel while the work was done for us by a team of builders...oh, how I laughed!
We're still renovating (in our mid 50s, downsized several times) and majority is still DIY as we really enjoy it, although I don't work these days.
DS has his own house (and young family) now and is renovating it himself whilst they both work, having learned loads from us, I guess. DiL doesn't do any DIY. DS seems to get way more knackered than I remember us being - perhaps because he has to do it all himself or maybe they just don't make them like they used to, lol!