One of the webcomics I read every day is Schlock Mercenary (like a lot of other people). There's never a day when there isn't a comic for that day (barring server failures, and even then, I think he's always gotten the comic up before the end of the day). By contrast, Real Life, which I also read every day, has a "no comic today" day every few weeks, because of the creator being out of ideas, having no time, being ill, etc.
So how does Schlock Mercenary do it? Simple. He's not working on tomorrow's strip today. He's always a few weeks ahead. If he gets sick, his buffer of strips will drop, and when he's better, he builds it back up. The Real Life guy, by contrast, does one strip a day, and has no days ahead.
Whenever I see one of his "no strip today" posts, I have a moment of feeling very uncharitable as I think, "if you just got a week ahead, that wouldn't happen," and then I berate myself: the guy's not making a living on this, and I'm not paying for it, and if he misses a day now and then, that's fine. Sure, it's not very professional, but that's okay because by definition he's an amateur, in the dictionary sense of the word. (Schlock Mercenary did buffering long before he quit the day job and made the strip his job, though.)
Some days, I barely get a blog post in, because I feel drained of good ideas (and don't have any on my "blog post ideas" pile that inspire me), or because I get busy and run out of time. When I travel, sometimes I can't get posts in. While a blog is often more "timely" (maybe a third of my posts are on something that happened that day or the day before), there's no reason I can't heed my own berating advice and start writing a few posts ahead. It'd just take a few days to write a few extra posts, and then I'd have a buffer; after that, one post a day would still keep the buffer the same size, so it'd be no extra work after that initial burst.
And yet the idea just doesn't grab me. The idea of coming up with a week's worth of blog posts ahead of time seems too daunting. So while I grumble about Real Life not doing the easy thing they could do, I'm not doing it either. Curses! Foiled by my own snarkiness.