These cheap scissors are held together with a screw (instead of a rivet), which means they can be tightened when they get loose and sharpened when they get dull.
I'm aware that the plastic handles probably disqualify these from being true "buy it for life", but the exciting thing for me is that they are relatively cheap and can be found on the shelf in most stores with an office supply section. It's an unfortunate reality that the vast majority of BIFL items are special order and cost several times more than their mainstream equivalent, so I wanted to shout out Scotch brand for maintaining such good serviceability on an item you can literally pick up at Walmart.
I just pulled apart a pair of these which was cutting horribly, gave each blade a couple passes on an oil stone, then reassembled and tightened them up with a drop of oil in the joint. They cut as well as the day they were bought, and the handles are still in good shape so I could see doing this several more times before I even have to consider replacing them.