Comment by xavian

Most of our instances we keep up for months at a time, although they can turn flaky. We tend to use EBS, so we reprovision instances when needed. The biggest overall issue we have with EC2 is clock skew issues that can fool our fault-tolerance layers into thinking there is a major timeout issue when it's only some clock skew. That and some instances randomly rebooting in the middle of a time critical processing operation. We primarily use m2.xlarge or m2.2xlarge instance types.