Thirty years ago a friend saw that I was going to the market and said, "If you find a metal mirror so I can adjust my tefillin, pick it up for me."
Whenever I would see street vendors or such a place that might sell them I would take a very quick look to see if I could pick one up for him. Last week I was buying little treats for some small children who were coming for Shabbos and I found something that looks great. It is very small, lightweight so it can fit in his tefillin bag, and although it was not made out of metal, it has two metal covers that should prevent it from breaking. It cost one shekel!
The next day I saw him at the Kotel and reminded him that thirty years ago he asked me to pick up something for him at the market and I finally found it. He had no idea what I was talking about but as soon as he saw it he remembered, "Oh for my tefillin."
Boy did I feel good being able to deliver it. Thirty years of looking!