How to Change Mower Oil

According to the lawn mower documentation, every 25 hours, or once per season:

1) Run the mower dry of gasoline.
2) Remove the oil cap.
3) Flip the mower over and drain out the oil.
4) Add 20 oz of SAE 30 oil.

Preferred method:

1) Run the mower until it stalls for no apparent reason.
2) Check the gas.
3) Run the mower until it stalls for no apparent reason.
4) Clean out the air filter.
5) Run the mower until it stalls for no apparent reason.
6) Let the mower cool off - have a bit for lunch.
7) Check the oil.
8) Discover that there basically isn't any left in the mower.
9) Add 20 oz of SAE 30 oil.

More steps, but the preferred method is easier.