It is a balancing act, and it changes over time. What I considered important to review at X interval last year, is perhaps not that important this year and so

It is a balancing act, and it changes over time. What I considered important to review at X interval last year, is perhaps not that important this year and so I lengthen the time between reviews (simply move the link). And at some point the content is firmly embedded and does not need regular review.