Almost every DIY mistake seems to have a moment where a quick measurement could have saved hours of extra work.

A cabinet that doesn't fit, a door that won't clear something, or materials that looked right until everything was assembled.

I'm curious what measurements people tend to overlook until it's too late.

This can get surprisingly important when putting equipment into a home gym, especially when checking ceiling clearance, doorway width, or whether a fully assembled machine can actually fit into the room.

What's a measurement mistake you learned from the hard way?

I may eventually cross post this, so if you see it elsewhere that’s why :)
We need help figuring out the best set up for our family in our small house. I’m finding it harder and harder to function as is. Moving is not an option unfortunately due to the economy. We hope to be able to secure a mortgage in about 1.5 years, but even then we won’t be able to afford a space much bigger than what we have. (Approx $300,000 max for our mortgage, which means little without knowing location etc).

Currently in a 1,250sq ft townhouse. Six kids and 2 adults. Living room 18x15, primary 14x12 with decent size walk in closet (we’ve often discussed taking everything out and making it baby’s room. Tiny, but doable), kids rooms are 10x9 and 11x9. Currently we have a king in primary (anyway we go we wi have to keep this bed), a triple bunk in the bigger bedroom, and then a twin with a trundle in the smaller. Obviously in a year or two we could put our one year old on the bottom bunk (sits at floor) but she’s too small now. But outgrowing her mini crib. Currently the only other place for her is our landing- which is decent sized but would require an extensive and much better top of the stairs baby gate. She’d also most likely not sleep well with everyone moving around her. We’ve discussed putting the 5 bigger boys in the primary and our bed in the bigger room 1 year old and our dressers in the second. But we still have the kids dressers and toys. We can’t put anything in front of windows that go above window sills. Window sills are about 8-10 inches off the ground. So that cuts a ton of area out. We’ve also discussed using the living room as a partial bedroom and partial living room. Or using the two smaller rooms as our hang out rooms and playroom and putting all the kids downstairs (I do not like this at all). We’ve even discussed loft beds for the bigger kids with futons underneath in the living room. We’d have couches that way and they’d have their beds we could put curtains around the tops of the beds. I’m just at a loss.

Important to note- king bed is newer and can’t be replaced. I hate the triple bunk but it prob needs to stay. Replacing the trundle option and the mini crib are the most obvious. We are a “living room” family. My oldest (11) hasn’t reached the point of needing or wanting his own space, but I know it’s coming. We do homeschool which has taken a lot of storage as well. Toys and clothes are at a minimum already. I just need to find a place for the almost 2 year old who isn’t ready for a “big girl” bed yet. And knowing we have a while I need better functioning in the home. I’m literally going insane trying to figure out what’s best so I’d love input. If you had to fit 8 people on this small space what would be your solution? Any I haven’t thought of?