We did it when I built our house… Bought a cheap 1980’s static for £1200. Lived in it for just over two years (sold it for £1k). First year while we saved money and slowly dismantled the concrete barns onsite. Second year, and a few months, while i built the house.
Went through the 2010 and 2011 winters in it, subzero for weeks and despite being as cold as i have ever been, it was weirdly fun too. We didn’t even have a plumbed in toilet and i built a composting toilet, outhouse style, next to the caravan.
We actually had a hard time moving out and into the new, warm, bright, spacious, economical house i built. I think we had become static caravan institutionalised.
We would do it again in a heartbeat, loved it really. Although we didn’t have kids then, might be a bit different now