All depends on birds and hours on wing I feel. Some birds just thrive on work, my best ever bird at 500 mile had 12 races in 13 weeks prior to 500 miler and came on day in toughish race following season would of been same but missed 3 races as hit wires came on day 14 and half hours on tough race. I like mine to have 80 miler prior to basketing(5 days) then leave alone just loft exercise. Prior to this at least a 350 mile race, and couple at 250/300. This would all depend on wind and race. If one of these was stinker then no need but if both quick and birds home in 5 hours be worried and get more time on wing. That short race before 500 race I like to be 2 to 3 hours on wing.
Know some birds can have very little racing and be jumped in these fanciers know family they have that is the long term aim to have 500 mile family. Thats if allowed to race the 500 mile races