So my first batch is in the carboy I put it in on Saturday and I followed the formula exact but the sheet says allow to ferment 7-10 days. So would I be best to split the middle or wait it out the 10 days?
The minimum you should be fermenting something, in my opinion is 2 weeks. Be sure to take hydrometer readings at the end of fermentation. You want to be sure that the gravity remains the same for 3 consecutive days so you'll be sure the beer is done fermenting.
Does your recipe call for a secondary? Personally I prefer to keep it in primary for 3 weeks or so then rack directly into a keg or bottles. It takes patience, but I think an extra week or so makes a better brew.
Don't go by time. Wait until the kreusen settles back into the beer, then check the gravity over the course of three days, if it stays the same, the beer should be done fermenting. Wait another two weeks before bottling or rack to a secondary and then wait two weeks.