I think that Briggs recommends to change the oil around 25-50 hours. It was 25 in 2003 with my John Deere L120 and I would imagine that is probably the same today.
If you read the operators manual in maintenance it will have the hours that you should do the oil change. Just be sure to change that oil filter.
If you read the operators manual in maintenance it will have the hours that you should do the oil change. Just be sure to change that oil filter.