If you take on temporary summer staff, they need the same fire safety briefing as permanent staff. Someone who doesn't know where the exits are is a liability to themselves and everyone else.
"Tested before every guest" is the standard that protects you. If something goes wrong and you're asked when you last tested the alarms, "regularly" isn't an answer. "Before every changeover, logged in our records" is.
Aerosols in direct sunlight can explode. Hairspray, deodorant, air freshener. In a hot car or on a sunny windowsill, the pressure builds. Not dramatic movie explosions, but enough to start fires or cause injuries.
Guests in unfamiliar buildings are at significantly higher risk in fires. They don't know the layout, can't find exits in smoke, and often assume alarms are false. This is why holiday accommodation has higher standards than domestic properties.
Kitchen extraction systems need regular cleaning, but "regular" depends on usage. A busy commercial kitchen might need monthly cleaning. Light use might be quarterly. Grease buildup in ducts is what causes serious kitchen fires.