I operate an Amada F0 3015 Laser, just started anyhow and i have a couple of questions maybe yall can help me with.....

How often do are you supposed to change the teflon Nozzle washer?? The operators I work with run their washers for a very long time I change them more frequently maybe once a week \
How often are you supposed to change your nozzle?? is it ok to run a dark burned looking nozzle if otherwise its in good shape? we run 3 shifts 5 days a week