I agree with Giuseppe. I am not aware of a rule recommending OSPF timer tuning for ISPs in a specific way or in general (i.e. if you are an ISP tune those timers and tune them like this). You know what they say: if it ain't broke, don't fix it. So, do you experience any specific issue in your network that made you consider tuning those timers? Such as: one core router rebooting and a second one crashing when first router boots or anything like that? Sometimes physical links can experience constant flapping causing e.g. increased CPU utilization in some routers. However, there are trade-offs between stability and speed of convergence as already noted by Giuseppe, plus you have to fix the physical layer problems anyway. Trying to keep your IGP as clean as possible (e.g. avoid redistributing customer prefixes to it and use BGP for those prefixes) is a more understandable procedure than IGP timer tuning, and can help keep your network more stable, since you only have to care about your own backbone links functioning properly when it comes to IGP convergence.