Major aircraft manufacturers have different AMM procedures for parking aircraft, Airbus have the best workable parking procedures that l have come across.
Airbus you can use parking requirements covering 7, 14 and so on, which you can repeat, these requirements are not classed as storage.
Boeing has always been a pain in the a***, with regards parking an aircraft which you do not want to fly for a few weeks.
It used to be, don't know if it has changed in the last couple of years, that after 7 days parking, all you had left was storage checks.
These checks would take a day or so to carry out, included using a protection compound on all leading edges and also doing so with any control cables.
It would take even longer to take out of storage and it would be very expensive and time consuming procedure.
Sometimes you could get around this by moving the aircraft so that the tyres are rotated and power up the aircraft, use the hydraulics, run systems including the APU and engines.
Ryanair are by the looks of it getting around using storage checks by flying the aircraft and using the parking AMM procedures.