Worn Nozzle? Multi Color Systems, Printing PETG and MORE!!

This Episodes Questions:

How do you know when a nozzle is worn out? if printing normal PLA and PETG, do you have an expected lifespan such as X kg of filament? Comparing cheap AliExpress nozzles of basic material with name-brand or special alloys or coatings, is longevity increased or is the gain primarily on performance and heat transfer? Ben

Thanks for the great podcast. I enjoy it a lot even if you're discussing machines, materials and techniques I'll likely never use myself! There are endless YouTube channels on the subject, but what I like about the podcast in particular is the discussion, and your willingness to challenge each other about views you hold, in a constructive way. Keep it up!I have an Ender 5-S1 and can print reliably in PLA now. Of course, it started out printing OK but went downhill as I experimented with it and destroyed and then replaced the surface plate. 
Anyway, now that I've got it all going I'd like to start printing PETG too. While I'm a lot more clued up now, the problem is I don't necessarily remember all the steps that led me to bring the PLA print quality back up to spec – I was just blindly following different clues and recommendations due to my lack of experience. If you were in my position, how would you approach generating a good profile for PETG? I'm thinking in terms of what types of test prints, and the order you'd do particular tests, along with anything else you'd suggest. Simon

Are the phrozen or even the anycubic ams or multi color units any good ? Are they just bambulab clones.
I love yalls content keep it up, Thanks in advance Tobias