The main thing is trial and error, what will work somewhere may not work somewhere else, you can use pop ups all year round, I think the main thing people seem to suggest is bright baits during winter and spring, then more match the hatch during summer and autumn when the fish are most likely to be feeding on plenty of bait and they may have been caught on bright baits already, but it all depends on the fish and on the day really, some people use bright baits all year round and catch, I think its mainly about the baiting situation and location