An unexpected major equipment failure or an unusually slow month can genuinely threaten a small gym's stability without some kind of financial buffer already in place.
Size the reserve to real fixed costs, not a vague number
Basing an emergency fund on actual monthly fixed costs — rent, salaries — gives a concrete, meaningful target rather than an arbitrary round number.
Build it gradually, as a standing line item
Treating a small, consistent contribution to this reserve as a regular expense, rather than an occasional afterthought, builds it up reliably over time.