Starwood Platinum is actually one of the easier top tier hotel elite levels to achieve, since 20 stays is not a lot compared to the competition. For example, Hilton's GOLD requires 16 stays, its DIAMOND 28 stays.

As for retaining it, you just have to face up to the reality that top tier is for those who stays at a chain quite a bit. Those who don't stay that much need to be content with one of the lower tiers, the benefits for which have been designed around the needs of less frequent guests.

Dropping a tier is never easy to accept, but remember what these programs are all about, and you will realize why elite is granted.