I've breast fed my first and I'm still going with the second (he'll be 1 next week). My second son was sleeping 9-10 hrs a night at 2.5 months. I know, it's rare. I was worried but my doc said consider myself lucky. He was gaining weight...basically he was feeding like an older baby. Nursing effectively during the day to sleep all night.
With that said, I slept too. I did not wake to pump because the milk supply is based on the supply and demand theory. If your son is sleeping 5 hours straight consistently then he does not need the milk during that time so you do not need to pump during that time (that milk supply will shift into his morning feed.
The major times that you need to pump is when your son is getting milk from a bottle. For example, you want to go out with your husband and you leave your son with a caregiver....at the time he/she feeds him your milk in a bottle, you'll need to pump as close to that time as possible. I would take my pump and do it in the car. Or wait until I got home and pumped immediately.
If you want to stock your freezer with a good milk supply, you should pump after feedings. Start pumping after one feeding for a few days, them two feedings and so on as much as you need or want. This will increase your milk supply. If you don't pump at all, I havent pumped in months, your body will produce exactly what your baby needs, no more...no less.
Good luck