After college, I found a great guy and got engaged. My parents told me to stay home with them to save for the wedding. I was very respectful in my parent's home; paid my on everything (including food), had very few guests, and helped around the house. Most of the time, they wouldn't even know I was there.
Moved back only once: when we transitioned to Texas and I was trying to sub-lease my apartment. Longest two months of my life.
Only borrowed money once ($1,000), when medical bills devastated my family after my daughter's premature birth. It was the first bill we paid every month until it was paid in full.
I knew a few people who lingered at Mom and Dad's well into their 20's. Perpetual children.
Makes it handy, Mrs WBill leans on them during the day for lots of grandkid-sitting. It's pretty much a win-win-win for everybody.
We've had a few lean times. Mom and Dad have always offered - "You can move back in with us if you need to." I've told them, "No offense, but if I ask, it means that we're 1 step removed from a cardboard box on a steam grate." It's still nice to have a net to land on, but nicer not to use it.
When my family was moving into a new house just recently, there were a few complications with the closing. We wound up staying with Mom and Dad for about a week while things were getting sorted out. Frankly, that was long enough. :-)
Some end up caregivers making life and death decisions for years so I caution anyone who discovers someone lives or lived "at home" past the day their 18th birthday rolled around to tread carefully.
Unfortunately, there's no support once that job is over. You've lost years (even decades) of work experience and retirement savings, not completed education plans, your peers have moved on and built families. You don't know where you belong in life because you had developed none of your own.
Parents owe it to their spouses and children to have planned for that possibility.