The insects would be in the pipe that is open ended outside that takes away the condensation that is formed as the gas expands in the unit and draws in hot air. The cleaning of filters is just as important as they get clogged with dust, insects, and such like.
Like anything left standing routine maint' should be done before using ,but as said before if they tell you it needs gassing because it's not used they are not being totally honest. Sometimes pipes can leak at low pressures and seal at high pressures, which is why they say it's lost gas through low usage, the truth is that it means that it has a leak which will only get worse in time.
