ORIGINAL: jepcho
The past 2 years I have been shooting 100 grains but I'm thinking about switching to 125 before this year. You can get wider cutting broadheads and for the most part they seem a little easier to find than the 100's. The 100's will kill a deer just as good as a 125 so it's your personal preferance.
By switching to 125 grains you could throw off your spine. You will get a weaker spine, which could be bad if you are underspined. A 100 will kill a deer just as good as a 125, but if that 125 would throw off your spine, it may not.