The question is very vague, that's why you don't get answers. Holding time for ''brandable'' depends on many different factors - how many of them you have in your portfolio, how you sell them (yourself or platforms) and also, your own opinion may change during the time (or may not). Today you see it as brandable and tomorrow - as a weird random made-up combination. Or could be the other way around.
I have around 50 brandables and I hold on to all of them for a few years now. Obviously it will be different for someone who believes he is holding 500 brandables, he'll sure be getting rid of some of them every year.
It's a tough market generally, but it's good to have them in your portfolio, imo.