4096 bit RSA keys offer very little additional security (2048 is plenty for at least the next few years, and with a certificate that's valid for 90 days, there'

4096 bit RSA keys offer very little additional security (2048 is plenty for at least the next few years, and with a certificate that's valid for 90 days, there's practically no risk - you can rotate the key rather easily if something bad comes along), but has a fairly big impact on performance and battery life, especially on mobile devices.