When should i replace nozzle?  

Alway have a spare on hand!

There's no real set time limit at which you must replace a nozzle. Wear will depend on your printing habits and materials. Nozzles can wear and can be damaged though, so you should keep at least one on hand as a spare. I luckily took the plunge of exploring different nozzle sizes early on, so quickly learned to keep a dozen or so on hand in various sizes. If print quality degrades, I'm prepared to toss one. They are definitely a consumable. I've only tossed a few over the last 3 years, usually when I noticed continual problems with clogs or fine stringing. They may have been recoverable, but I'd rather have a known-good nozzle installed considering the potential impact.

When looking at spares, avoid the mistake of going for the really cheap stuff. I've written up some detailed notes on this, but in short: Cheap nozzles often aren't machined with the correct geometry to get the best print quality.  E3D, P3-D, TriangleLab, and a few others use precision machining with dimensions that vary depending on the nozzle size. Cheaper brands simply drill differing size holes in the same blank.

Thanks

Thank you sir. Valuable info from the front line. I will order a couple to have as spare and note your advice concerning getting a good quality nozzle. The nozzle appears to be the most critical component in the whole setup so stands to reason it should be of the best quality. Think I’ll stay with the manufacturer that came with the machine until I have more experience and am knowledgeable enough to explore others.  I will keep the first items that I printed as a reference and when clogging and stringing increase will reprint the pieces and make a comparison. 

Posted by: @dai-wee-mike

Thank you sir. Valuable info from the front line. I will order a couple to have as spare and note your advice concerning getting a good quality nozzle.

I've gathered all my notes on nozzles here. Some of them might be useful to you as you get familiar with your printer. Happy printing!

Nozzle replacement

I replace them when they start jamming too much or the print quality drops because the nozzle diameter appears to be increasing.  

The challenge …

For me will be to recognize when the print quality is dropping off. I suppose in the future some sort of alert will be incorporated into the software after a certain number of hours in service a la my car. 

Experiences

Depends on how much you print. With a LOT of printing, I got a full year out of an e3d Nozzle X (including printing PC and other abrasives).

For normal nozzles, generally up to 6 months and a bit less if printing a lot. Copper nozzles are very good, but softer than brass and don't last. Generally if I start getting poor surfaces and poor adhesion and cannot fix it any other way, I replace the nozzle.

Posted by: @dai-wee-mike

Hello all:

Relative noobie but have been printing a lot since my Mk3S+ arrived. It’s been an amazing piece of equipment with perfect results straight out of the box. Best decision I ever made was to get it pre-assembled - eliminated one variable from the start. My question though is when can I anticipate replacing the nozzle? I am mainly printing PETG, PLA and LW-PLA and the results are still super sharp, but are there signs to look for when the nozzle deteriorates or do you suggest a certain number of print hours/days in service before replacing? Thanks, Mike. 

Ta the feedback.

I’m thinking 6 months is a nice round figure so will start off with that and adjust accordingly. It’s my favorite hobby at the moment so not a huge investment in a critical component of the process 

Nozzles

I think 6 month is a good place to reassess.  I have a couple nozzles that are 1-2 years old and still going strong.