i have two brassica beds - one for long standing overwintering stuff - should be cleared by about april
one for short term stuff - broccoli and the like, which is mostly cleared in late autumn by the first frosts.
as i move my rotation around, the roots that follow are also divided into long term and shorter term ones, so i have some that need to go in early (in last tear's short term brassica bed), and othr things can go in later (in last year's long term/overwintering bed)
this also works for the bean bed - where the o/w stuff is onions, leeks and garlic, followed by french beans in early summer, and the other bed (cleaned in the previous autumn) takes early broad beans and peas, followed by suqashes or more peas later on.
it seems to work ok this way (and my brain doesnt hurt too much)