Assuming from your post that this is not a budget constraint issue and you have good wallet discipline, then that leaves you with time management as the crux of your question.
When I have what I consider a full roster, I typically split my SB's into an A-List and a B-List.
The A-List are my regularly scheduled and generally best price/performance SB's. I make sure to mark my calendar with these dates (generally every 2 weeks, alternating) and make a point of not scheduling other dates 2-3 days before and after my regular meetings.
The B-List are my "stand-by" SB's. They may not be as much value based on price/performance, or they may not have predictable schedules (due to travel, family, bill due dates, etc.). But since at least one of these is a hard fuck value taking essentially pocket change (maybe $100-300), and one of the others is a high-allowance porn star, I'm good with seeing them less often. I make a point of not accepting a BCD with these within 2-3 days of an A-List date. No point spending a little money now only to waste a lot of allowance in 2 days if I can't really perform at the level I want.
That all means that although I have roughly 7 SB's on my roster at any given time, I go BDC only around once a week.
PS: That essentially leaves hookers, AMP's sessions and OTC/ITC strippers as my C-List.
Life is good
The Cat