How often are you allowed tourist visa for Thailand?

Hi,
Sorry if this has been asked before. Im currently in Thailand on a tourist visa that I assume allows meto stay for 60 days. If I cant finish my business within that period. Am I allowed to apply for another tourist visa to enter Thailand again after I get home? If yes, do I have to wait for a period of time before I could enter Thailand again?
Lastly, whats the limit for numbers of tourist visas one could apply in say, a year? And how long does one need to wait between each intervals?
Thank You.