The nozzle is a wearing part: Average life span between 600 and 900 hours of printing depending on use. The use of filled (abrasive) material is not included in the calculation of the service life.
When a nozzle becomes tired: under-extrusion or/and repeated clogging, also replace the thermal barrier. This last one is in continuous solicitation like the nozzle.
For more information on the maintenance of your printer’s components, here is the link to the article: Maintenance