hello and good day everybody. my trusty old mower finally bit the bullet the other day. ended up getting a new mower. wanted to see if the Bitogers changed out early the motor is a briggs and stratton and did not have oil in it at delivery.I added the 18oz of sae 30 that came with it. put some gas in the tank ( gas had neutra 131 in my gas can ) and cut my lawn the other day. was thinking of changing the oil out early or sould I just run it until the last cutting then change it like I usually do, before I put it away for the winter. also thinking of using synthetic 5w30 since I have a bunch of it around. I have M1, royal purple , PP. what say you ?