After learning a certain oil change facility does not always change the oil filter when doing an oil change I went back to doing it myself. Things have changed on the motor oil shelf. So many choice...
I like the idea of using synthetic and changing oil every 25000 km. I kind of think if my oil level was below the add mark I would end up changing it early rather than adding regular oil to top it off. As it is I never check my oil level so adding is not required.