hi Guillermo,
What type of kite did you end up buying

?
Along the same thoughts as Burkey Boy & Spawn, ( he beat me to the keyboard with this reply), the enemies of your kite are:
- sand, this goes for lines as well.
- packed away still wet/damp from fresh water.
- constant flapping of the canopy (usually while waiting on the beach).
- extreme temperatures eg. in hot car for lengthy time.
- and of course dragging/abrading along rough beaches, rocks, not to mention trees & bushes etc.


Our family tend to do similar to Burkey Boy's methods.
If un-rinsed we hang the kites to dry then carefully (with a soft brush) remove any sand seaweed etc. It is amazing how much sand your kite can collect, especially if it is wet when you pack up.
If possible a freshwater rinse usually removes most debris.
I rinse any pulleys, wait until dry, then carefully apply silicone dry lube spray to keep them working.
I rinse & dry my bar & lines as often as I can as sand can abrade your lines.
Maybe we will see you at Parham on the next good wind & tide

regards
fossil