In the winter months I substitute teach at a few local schools, today I was approached about submitting a bid for mowing their schools... Two are small, less than hour jobs... The third is fairly large, I am GUESSING it will take me about 6-8 hours.. The 4th one is huge, again I am GUESSING that it will take about 15 man hours.. This would be my first job that takes over 4 hours and I am nervous tossing a bid out there... Any suggestions??