Real-life experience blocks to aid 6-point leveling system

If you camp on paved driveways with no slope, you won't need blocks. But we've needed them on several occasions when parked on dirt, in fields etc. We keep a storage bin full of them in our basement storage. We had a trip this year where we were on a site so unlevel, we ended up with the front jacks nearly retracted all the way, and our rear drive's side needing to extend all the way, plus some blocks under it.