[R-sig-ME] glmer does not converge, how inaccurate is using nAGQ = 0?

[Paolo Fraccaro]

Hi 

I have a dataset of ~200k piece of hardware tested yearly for 10 years or 
until failure (~15k). Therefore, the overall dataset size is ~2,000k. I'm 
trying to fit a mixed effects logistic model with glmer, but the model 
does not converge with the default settings. I tried to increase the 
number of max iterations allowed (from 20 to 100) but still it does not 
converge. I then set the nAGQ = 0 and obtained the less accurate estimate 
of the model.

My questions would be:
Do you have any idea of what parameters I could modify to try to make the 
model converge?
How inaccurate is using nAGQ = 0?

Many thanks.

Paolo