Guys, why don't you answer text messages?

So there is this guy I like, and sometimes he texts back, but then will stop mid-conversation and it'll take him a few hours to text back again and occasionally it'll be the next day. He does always respond back, and I know he has a really busy schedule so I don't get upset about it, but I'm just wondering is it because of his schedule or is it lack of interest? I don't want to get on his nerves but he told me he would tell me if I did, so I try not to text him as much unless he is responding back. Is it because he is busy or is it he just doesn't care to talk to me?