It's not just about the years spent in retirement, but what you're doing. This is something I heard from a financial advisor - Retirement happens in phases.
Go-go phase. Years spent in relatively good health. Add extra budget for travel or big-ticket items to enjoy, like an RV.
Slow-go phase. Staying close to home, maybe spending time with grandkids. Increased medical bills.
No-go phase. No travel, but largest medical bills.