I deadhead my Harlequin (a small, seed-grown decorative dahlia) whenever the blooms fade. Production of new blooms is constant, so it always has buds, fresh flowers, fading flowers, and things I really should dead-head and promise to get around to shortly.

As far as I've noted, my medium-sized semi-formal dahlia are the same, and I've never seen an exception on any dahlia type I've grown. Most seem to constantly produce buds. But I feed a lot.

If you were--let's say--to remove every bud, it would probably be 2 to 3 weeks for the next set to develop.