I learned the hard way when rebuilding my plane that the perfect may be the enemy of the good, but "good enough for now" always meant I'd be going back and redoing the effort again later, to better standards.
I failed to apply this to my knee. I can walk, and I even climbed a relatively low and easy mountain twice, but I haven't really run. I don't play tennis, or go dancing, or scrambling to play keep-away with a dog or child. I haven't been climbing trees, or hiking regularly. And it shows - my hand-eye-foot coordination still isn't what it used to be.
I haven't done anything involving quick changes of speed and direction with my feet - no wonder they're not there on the rudder, and it took more time and practice to get them alive. If I want to have lively feet, I need to go ballroom dancing. Or at the least, go play tennis or basketball.
Also, for endurance in the plane, I need to go do more aerobics - and while I'm wheezing on the elliptical or treadmill, I need to be studying instead of zoned out to an MP3 player. This isn't for being in shape or so I know the material, but for practice on concentrating when exhausted - because no matter how tired I am, I am still responsible for being in control of the aircraft, and landing it safely.
You can coast in a lot of areas in life - but if you don't push to get that last 10% regularly, it's not going to be there when you need it. If a thing's worth doing, it's worth doing well, from exercise to flight planning to mopping a floor. So, even if I really feel like surfing the internet, I'm off to the gym with a copy of Stick and Rudder.