Comment by convolvatron

I build lights with cob modules with phosphor (bridgelux), and unless I screw up the thermal interface, I get many years out of modules that cost < $5 each. one thing is that the thermal paste is too fiddly for most people, voltage/current tends to drift around and 0.5V is a big difference here. mechanically they tend to use a couple different form factors, but not 100%. the 10 watt units I had been using were bigger than the 15w I use now, and the mounting spacing went from 0.75 to 0.71

I would hope that at least some of this would get standardized over time