Should be able to have builds that are scheduled via a cron "build strategy" execute only if changes where found in the repository. This way you could ensure that builds start e.g. at the full hour only (8:00, 9:00 etc), so when you commit code you don't have to wonder (or bother to check...) if you just missed a build or how soon to expect feedback from Bamboo. This is even more important if builds are done even less frequently.