You are really asking for problems flying that many times on a 600mah battery on any plane. It becomes a matter of time. The only real way to know for sure is to use an expanded voltmeter (one that properly loads the battery) and checking to see what the voltage is before going up. It it is anywhere around 4.9 I would NOT fly, I would recharge.

What's the problem, anyway!! Recharging seems to be a simple solution, or at least a precaution to prevent a crash, eliminate that bad link in the chain of events that causes crashes.

Go to the people that make chargers.. sirius for one, has a pretty good section on batteries and the do's and don'ts about batteries, and he will tell you that it's a simple matter of math. Four servo's for 5 10 minute flights simply does not add up, and you are definitely headed for a crash, even if you can justify the last crash as not being from a dead battery, eventually, at that rate, you will have one. It's not if, but when.