Climb Strong’s website writes about doing “the minimum necessary training to see continued progress.” If you want endurance, train on not so hard routes for longer time. If you want power, train on hard routes for less time. Read all of the details at the link.
“I’ve said it before-fatigue creates endurance, heavy loads (difficult moves) create power and strength. So it works really well to build power when you don’t have tons of time. Test this yourself. Write down all the problems and grades you send in your next bouldering session. Note the session length, level of fatigue/soreness post-session, and the number of days between sessions. Now, reduce the duration of your session by 25%. If you trained 2 hours, train only 1.5 hours next time. Do a couple of sessions at this new duration, keeping the same notes as before. After 2-3 sessions of 1.5 hours, reduce your time again by 20-30 minutes. Repeat the process again, then reduce again, in our example, you’d drop to 45 or so minutes per session. What you’ll see is a drop in volume (duh!), but an increase in overall performance at high levels.”