Interesting what you say about smell as a stimulus for memory.
For as long as I can remember, I have associated the smell/taste of certain tomato sauces with eating tinned ravioli at my grandparents' neighbours farm. I remember the outside of my grandparents house and the approach to the farm, I remember the farm kitchen clearly. Every time I smell that smell, I see it and I can't eat whatever it is.
Only last year, when describing this memory to my mother (after being served a tomato dip), I found out that my grandparents moved from that house when I was two and I would only have been there a couple of times. I only visited the farm once and that was the day of my father's funeral, a week after my 2nd birthday. I have no other memories from that age, but a certain smell has clearly helped anchor one very significant occasion into my mind.