The level of strength and fitness you need obviously depends on what you’re training for. What you need for day-to-day living is usually less than what you need to climb one of the Everest Base camps.
No surprises there.
But as with money, you want to have a bit more than what you need. You want to feel you don’t have to spend everything you’ve got to just get through the day. And it doesn’t hurt to have some reserves, for those just-in-case moments.
When the neighbour needs help moving the grand piano. When the only way to avoid a public meltdown is to carry the tired kids or grandkids through the airport. When Robin’s too tired and Batman can’t be bothered. And you’re definitely not going to call Spiderman. Because laaaaaaaaame.
And if you are climbing the base camp, I’d say you don’t want to feel completely wiped out before heading back down.
It’s easy to get caught up in doing more for the sake of doing more.
But it’s just as easy to deceive yourself into thinking that you’ve got enough.