Boil overs. They happen. I've been brewing near to 5 years... I STILL boil over, unless I'm standing next to my kettle for the full hour. I tend to be in the kitchen, doing other tasks (making up breakfasts/lunches for the week ahead, helping with dinner's prep-work, etc.). I was actually quite proud with the batch I just brewed (and is in day 9 fermenting) because I was able to do other tasks and NOT boil over.
As for the Hydrometer, I agree with those above, it's not essential to brewing, but is darn close. Like a speedometer on your car. Not necessary to get from home to work, but is a key tool to help you avoid a large number of issues. I have broken many hydrometers, and my recommendation is that you only handle it at the point where the fat and skinny parts come together. That is the weakest part of the hydrometer (and where every one of mine has broken).