Yes, but the difference between most creators and serialized manga artists is that serialized manga artists have editors to keep track and pay attention to that sort of stuff (especially since the editors can often be the ones offering direction in how a story should go - that's their job).
Most creators are working on their own (and I say most because yes, some are working for companies, ex. Mikiko, and others are working with writers/artists as a team, ex. Reon Merryweather) and so it's best to start practicing and getting into the habit of crafting a good story through and through instead of trying to wing it. There's no downside to it - all it does is help you work out kinks in your story, make sure everything fits and works, and assures that you'll tell the best story that you can produce. Winging it only works for some people, and most of those stories are shorter and not as long and complex as series like One Piece, Bleach, Naruto, etc. (IMO, Bleach should have ended after the Aizen/Hueco Mundo arc, at the end of Volume 48; and One Piece isn't even half-done yet!)
Not to mention, while it still stands as one of the most popular animes to date, DB is not a good example of a well written piece of work. It's inconsistent, most of the love for the series comes from nostalgia and the high-action fight scenes, and DBZ has been said to be even worse. Lots of people love the Cell/Freeza/etc. saga but that was considered the highest point of that show, and everything else got most of its charm from its crazy martial arts sequences. The story itself is all over the place, and you're not really justifying your point by pointing out the fact that Akira Toriyama made it as he went along - cause if you look really closely and actually start thinking and looking for the plotholes/inconsistencies/etc., you can really, really tell.
(that being said I do love DB and have nothing against it, and don't want to start a fight over that lol DB is an awesome show/manga <3)