As long as the comic I'm looking to subscribe to has regular updates, it's unlikely that I'll be put off. If they can successfully maintain regular updates for multiple comics, then that's points in their favour, because it's not an easy thing to do.
However, if it looks like the creator has a habit of starting comics, keeping them going regularly for a little while, and then abandoning them for a different comic, only to repeat this again in a few months' time with the next idea, I might be hesitant to subscribe. Running a webcomic successfully requires a huge amount of discipline, and if I'm going to get invested in a story, I want to know that the author has this discipline.