I’ve been wearing 501s for longer than I can remember. Decades. I buy the non-prewashed, shrink-to-fit ones. I haven’t found that the sizing or the cut has changed – they seem the same to me as always. I will say that I have noticed that the sizing of Levis products in general (not just 501s) is wildly inconsistent – two pairs of, for example, jeans, both labeled with the same size, may vary by as much as an inch in either dimension (waist and inseam).