Using /31 for router links

[Seth Mattinen <sethm () rollernet us>]

In the past I've always used /30's for PTP connection subnets out of old 
habit (i.e. Ethernet that won't take unnumbered) but now I'm considering 
switching to /31's in order to stretch my IPv4 space further. Has anyone 
else does this? Good? Bad? Based on the bit of testing I've done this 
shouldn't be a problem since it's only between routers.

~Seth