Less each year all about fine tuning and how easy to work. I want to retire selling names that will sell rather than hoping. I still delete loads of domains and should have slapped myself last year hard and year before harder.
Also, for domains with significantly different first and renewal rates, it can make logical sense to try a domain name for a year, but not plan to renew it unless a significant offer or other strong indicator, like parking revenue. Many of my experimental are in that category.