There's definitely a lifetime on lipo's. Sometimes manufacturers specify cycles.. It all depends on how important speed and capacity are to you. One rule of thumb is that if it no longer holds 80% of it's rated capacity you can consider it EOL. Generally you could expect around the 200-300 cycle range. Worse case scenario you put about 160 cycles in already. And that doesn't account for properly storing, etc... so you're probably about there.

5-6 minutes would definitely not be good enough for me so i would be replacing it with something bigger or newer.