The bathroom vanity in the guesthouse I just moved into is the original from the early 1950s - no drawers, just a deep opening with no shelves or anything under the sink.  I have arthritis and could not bend down and reach under the cabinets to get anything, therefore all that space was lost to me.

Fortunately I found these organizers - I bought two of them and had my handyman install them (piece of cake, he said) - one on each side.  Now I that space is usable again and I can reach what I need without having to climb under the cabinet.  WONDERFUL!  My only critique is that they become a little harder to pull the farther you pull them out.  However, that may be by design so they don't pull out too fast, jostling the things in them.  The storage capacity of the baskets is far larger than I expected, which is GREAT!  Highly recommend these!