How many times can you wear a N95 mask before replacing it?

As a professional practitioner in the field of cryptocurrency and finance, I often find myself wondering about practical day-to-day issues beyond the digital realm. For instance, with the ongoing pandemic, the question of personal protective equipment has become increasingly relevant. Specifically, I'm curious about the lifespan of an N95 mask. How many times can you safely wear a N95 mask before it requires replacement? I understand that the mask's efficacy in filtering out particles depends on its integrity and proper usage, but I'm interested in a general guideline. Is it a matter of hours, days, or even weeks? And what factors should one consider when deciding whether to replace their N95 mask?