I do from time to time. I tend to add series to my subscriptions as a sort of "to read" list, and I will usually just go through them when I want something to read. Sometimes the series isn't for me, so I unsub. Doesn't mean it's bad or anything.
I don't really pay attention to when they've last updated, but I'm more likely to read a series I get notifications for being updated regularly because it means I can keep up with new updates.
I don't keep up with a ton of comics, but the ones I do I'm always super excited to see when they update.