Purple sprouting broccoli doesn't grow a big central head like storebought broccoli; it grows little shoots all over the plant, which are time consuming to harvest, I'll admit. The first shoots are picked--I use scissors--then new, smaller shoots grow in their place which are then harvested, then new smaller ones grow, and so on. This plant is a labor of love, from its long growing time to its little-by-little harvest. But it's one of the few vegetables to be harvested this early in the spring, and a very welcome change to our diet: particularly if we were eating solely from the garden (wish we were but not quite there yet).
I have around a dozen plants, all in 2016's peas/beans/brassicas bed, except for two which somehow evaded notice in the old holding bed. Now they're all sprouting, I expect to pick them every two or three days--left too long, the shoots will flower, which are still edible but not as nice (a bit soft for cooking, and spicy when raw). There have been years where I let them get away from me, and lost a large proportion of the harvest to flowers. I'll be diligent this year and if I have to, will freeze any excess. Hopefully it won't come to that though, and we'll eat it all up as it comes--it's laborious enough without the extra preparation of freezing!