Drains in a house used a few weeks a year behave differently from ones in daily service, and the problems are their own.
Traps dry out
In a home standing empty, the water sitting in a drain trap slowly evaporates. Once it does, there is nothing sealing the drain and sewer odour comes back into the room. People often assume there is a serious drainage fault when the answer is simply running the taps for a minute in each unused bathroom.
Sand and long runs
Island houses take in sand from the beach, and large floorplans mean long drain runs with gentle falls where it settles. Jetting flushes it out rather than making a channel through it.
Heavy use in short bursts
A house that sleeps ten does a month of normal usage in a long weekend. Lines that seemed fine can block under that load, and it always happens when the house is full.
Best cleared between visits
For a property used seasonally, having drains cleared before the season rather than during it is far less disruptive — and easy to schedule with your management company.