I don't pull my jumpers mane. It thins it out and makes it look flaky and juvenile. So I comb the hair all the way down and then use scissors and slowly using my hand as a guide length I cut across the edges. (I know awful) but my horses mane is thick and gorgeous and I get complimented on it often.
Pulling them is good because it'll make it easier if you have to braid for a welcom or a Sunday or something like that
Pulling it is the healthiest way and takes a long time but u can also use scissors