If it ain’t broke…….don’t fix it.
By that i mean don’t replace gaskets/seals etc – and as for descaling?, has it been used in a hard water area? – if so then just run it till you get a problem as attempting to descale it will most likely lead to deposits getting stuck in the solenoid valve that bolts onto the boiler head. If this happens then you will get steam quite happily but no water from the group head.
About the only item i’d replace (if you notice a problem) is the filter basket and shower screen as they get clogged over time, and the grouphead to filter holder chunky rubber seal.