that really depends on the size of the snake: grease is a *huge* nightmare; this is why restaurants have grease traps. i've seen video tapes of (the insides of) sewers before they've been cleaned and the drains outside the average take-out chinese place are not pretty -- quantifiably worse than outside, say, a pizza shop. this doesn't imply anything other than more grease is generated as a by-product of the cuisine. as a landlord (at least where i live) you have to suck up and deal, either providing preventative maintenance (and the drano comes in handy here) or by not being a landlord at all.
mini rant: my two cents is that the "not be a landlord at all" option should be considered by more people who take it on. as a renter i'm not just paying your mortgage instead of mine because you provide a roof. maintenance and upkeep (and snow removal!) is a service that i'm paying for and expect. the landlords who think it's all "wait for the check to come in" don't get it and should get into some other line of work.