How long can you stay in Spain without a visa?

Could you please clarify for me, how long exactly am I allowed to remain in Spain without the need for a visa? I'm interested in understanding the specific duration that is permitted for individuals like myself who are not required to obtain a visa for entry. Is there a specific time frame, such as a number of days or weeks, that I can adhere to without violating any regulations? Additionally, are there any conditions or exceptions that might affect this duration? I would greatly appreciate your assistance in clarifying this matter.