You should replace the group gasket (MC930-2) and screen (1600069L1) every 6 months, if you leave it longer the gasket will get hard and will become difficult to remove it from your machine when you do eventually change it.
Parts included in this kit:
Every 2-4 years you should also replace the steam boiler valve which you will find here: https://www.homecoffeemachines.ie/products/lelit-anti-vacuum-valve
This person will show you how to replace the group seal and screen, they make it look easy :)
