Ask your host if you have any F&B comp on top off the room comp. If your play isn't high enough to warrant an upfront F&B comp, he/she might mention backend comps to you. Backend comps is any comp you receive after they evaluate your play and your play "paid off" for the comps you already receive upfront. Never take advantage of a comp if you don't plan on playing at the same level as before, unless you don't care about your future offers or relationship with said host.
8-10 hours of slotting is some serious play time, especially if you're betting $3-4 a spin.