In reply to Exile:
The thing I generally do is laps down the wall, aka 4x4s.
One winter I started off doing a vaguely periodised type thing starting off with aerocap (10 mins on 10 mins off, low intensity), then going to 4x4s (higher intensity at about 3.5/5 pump) then starting to throw in a bit of PE (redpointing). All the while, I'd keep up one bouldering session a week to keep up my finger strength (not a limiting factor for me on routes).
Did it work? Who knows, that summer it rained every single day and I never went climbing.
This year, I'm doing lots of laps again but with no method. I just try to do 16 or 20 routes every time I go to the wall, in blocks of 4 or 5, sometimes just keeping the intensity reasonable, sometimes trying hard stuff and falling off, sometimes just working to utter failure. No rhyme nor reason. I also boulder about once a week to maintain finger strength.
I think that this no rhyme or reason strategy is probably pretty good for trad training: sometimes you need to hang on to big holds for hours, sometimes you need to do a few hard moves on crap holds to a rest, sometimes you need to pull off a desperate crux. You need to be fit and adaptable. As such, I think my non-strategy is probably jolly good, let's see how it works out next season!
Post edited at 22:07