I check about 95% probably. I won’t buy an expired item from the supermarket, or something past it’s sell by date. I don’t automatically throw out food that is past the dates in my house though. It depends what it is and how far past the date. If milk still smells and tastes good then it’s good, although if it’s more than a week past the date I’d probably still throw it at that point. Eggs I use past the date all the time. I do the water test. Bread I use past the date also, especially if it has already been moved to the fridge.
Note: if your sense of snell is diminished it really creates a problem, it can be downright dangerous. As people age this sense can become less accuse just like eyesight and hearing. Not that you have to be older to have a bad sense of smell, I’m just making a general statement. Sense of taste also lessons over time, even separate from the sense of smell, but of course sense of smell plays an important role in taste too.