It's really dependent on how comfortable I am with that person. If they're someone I'm close to that I talk to on a daily basis and see often, then I don't care how many times I text them in a row. However, if it's someone that I'm just starting to talk to, I don't want to give them the impression that I'm annoying or pestering them, so I try not to unless it's urgent. Unfortunately, this is really difficult for me because I'm naturally a chatty person, and love having conversations with people, so when they don't respond after I while, I want to keep it going D: