Doram - well… it’s a different prospective on a lever group, or a ring group like the Elizabeth, or Rancilio Silvia, or Gaggia Classic etc vs an E61 group.
Reason I say this is that on the E61 the gasket comes down as part of almost daily maintenance, I.e.: to wash the shower screen and gasket every couple of days. On the other two types of groups, the gasket never comes out, until it fails, or there’s a need to do some sort of deep clean or maintenance of the group, which is not very often at all.
Doram, if you haven’t replaced a rubber group gasket in two years, it must be pretty hard and baked by now. It might not be broken as it’s still doing its job, but if you replace it, you’ll notice the difference straight away.
