Tile Match: Find Pair

Please keep creating memory improvement games as these are for quick reaction motion

I have problems seeing some of the things I am suppose to match. As we get older that is a common problem & I believe I am not the only person who has this problem. Possibly a larger print version like books have.

Just had this game for two days and really like it, but I have questions. Sometimes when I match, the tiles don't go away. The three hints below: will they build back up or do I just use those and don't get any more? What triggers a mix up of the tiles? It is really needed sometimes Thank you so much!