Not a bad idea about keeping some spares in stock.
I learnt the hard way about how important it is to have them in good nick cos mine started to perish and there was just the slightest crack in one where air got sucked in.
My speedie was pis#ing and far#ing like no one's business until I replaced them. I think from memory (don't quote me) but the squirrel condoms you get with the A1 set are good for about a year before they start disintegrating.
Keep an eye on those one's peoples.
Now I have really good quality ones where I continally treat with Armoral and they seem to be staying in good nick.
