The label on the bottle is going to denote exactly how much and how often your dr wants you to take it. Whatever was written on the prescription will be written on the bottle...only in a language normal people can understand
Sounds like your dr is giving you some leeway in how much you take. That seems a little odd for a med like buspar. Benzos are often prescribed as an as needed med because they are fast acting. I'm 95% sure that buspar needs to be taken every day, and like anti-depressants, it will take a few weeks to reach it's max effect.