There’s nothing like an “airdate” to move the process along! I assume that you’re talking about projects with “soft deadlines”. My suggestion is to put it in writing!
Many contracts specify a timeframe for responding. For example, if you turn in a cut (delivered electronically or on DVD) the client has 48hrs in which to respond. A delayed response can
move the final delivery date later, and therefore trigger “cost overages” for which the client would be
responsible.
Frankly, if the client can’t/won’t respond in two days, you know you’re in for problems. If they won’t agree to this in advance, you’ve been warned, and should adjust your bid accordingly.
With NO penalty for slow response, the burden is on YOU. That’s just dumb. Spell it out in advance. The time frame for response, and the NUMBER of passes the client gets. This forum is filled with horror stories of the client from hell demanding dozens of passes.
Good luck.