In my case, I do'n't have no other choice but to hold because the price of some of my alts holding are low, having no trade volume and some are showing signs of recoveries in which I think holding for a little longer would be more beneficial than selling at this point especially to those alts which are included to the 'mainstream' ones. I am hoping still that the prices would go higher upon the halving, so I decided to wait for a little longer.
Taking profits at the right time is good, but I think for some quality altcoins with use-case are good to hold in the long-term.
I do believe that what could happen to Bitcoin's market value after the halving could reflect to the market price of some altcoins that I am holding which boosts my patience to not sell at this point despite of some redmarks we are seeing. There could be chances that the market prices can still climb their way up which could generate more profit. And for those that won't, i would probably hold them than to lose money from selling at this low point.