Methods and Equipment for Measuring Nozzle Wear

I understand nozzle wear can be measured using a microscope. Is there alternative (i.e. cheaper) equipment that can be used?

Also, I just change nozzles every 3 months or when things start to go wrong in a manner that implies it might be related to the nozzle. Are there actual signs one can look for, fancy gcode programs that can emit a line you can measure, etc?

Thanks in advance for replies.