I had one before but can't remember at what stage it was in. I think after it flowered.It has been awhile since I had one with a flower.
I have one, how long before a new one flowers?
Blacky1

It's primarily the leaves which are needed for energy conservation. The leaves of bulbs are left uncut as long as they are green, which may be a couple weeks or up to a couple months or longer. I have some lily bulbs which have green leaves from early spring to after frost, although they only bloom for a few weeks in the summer.

A general rule of thumb is to cut the blossom stems after the blooming is finished, usually when the stem turns yellowish. If you are saving seed, then the seedhead should be completely dried.

Blacky1 - Local to me, most yucca blooms annually, that is, once a year. However, there are several species, and I think I've read that some species bloom only on established new growth (2 year old plants?). I also understand that an excess of water can deter the blooming.