It depends. Internal tools that are specialized for the industry or a specific business process at that company are probably fine and necessary. But I've seen m

It depends. Internal tools that are specialized for the industry or a specific business process at that company are probably fine and necessary. But I've seen many instances where a developer or manager gunning for a promotion writes yet another build server, deployment system, content management system or what have you just to have a "trademark" project that they can take credit for. It's that sort of internal tool which one should be very wary of, since they tend to get deprioritized but not abandoned. That is to say, once the person who championed that tool has received their reward, their continuing priority is to ensure that the tool sticks around (so that they're not blamed later for writing a tool that was later abandoned) but not necessarily to improve the tool on an ongoing basis. You want to stay away from situations like that, because you'll be assigned with fixing issues and putting out fires as they arise, but you won't be given the resources to properly refactor the tool to ensure that issues never arise in the first place.