[oldschool1982]

Headless, 1-1/2 weeks????? Eeeee Gads!!!!!!! Must not be that high of volume. Hehehe. (please... No offense meant) But in all seriousness any kitchen I've been in we were luck to get three days outta grease. We always had one fryer with nothing but new grease (fries and chips only) then it went progressively down hill for the remaining fryers with the oldest usually changed out frequently.

As far as Home fryers go there are some pretty nice ones out there now. Definitely not of the Keating caliber (0-360 in under 10 minutes) but I've heard they can be heated in 15-20 minutes or so. Recovery is something else. On the stove top is quicker but much more dangerous. Trying to impress my wife (then girlfriend) with a meal of fresh fries and smoked chicken on a crapy stove. Not a good combination in the cramped space of my condo kitchen. Doohhh!!!! And yeah I'd been cooking professionally for 20 years at the time.
As far as a Home kitchen shelf life for the grease? Something to think about is if you do mostly taters and the like once or twice a week then maybe around 2 weeks. But once you start with meats, seafoods and different frozen items.... IMHPO I wouldn't push it past a week. Not really worth the side-affects. Plus the grease will have an odor that is unmistakeable if it goes south. Hot or cold. You could always use the old tried and true "Florence Henderson test".