We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "john hamilton"
saying something like:

I find those small rubber 'O ' washers ( 15mm dia x 2mm ) that seal the
garden sprinklers and hose fittings seem to split after a year or two. Mind
you I do leave the sprinklers out in the weather all year.

The last time i bought a few from a garden centre they were expensive.
Would anyone know where to buy a small bag of them reasonably? Thanks

You could get a box of assorted O-rings from Screwfix, etc.