Many blind and low-vision knitters have a problem finding a good way to keep track of what row they are on. One device I’ve found useful to count rows is the score card from APH.
These score cards are about 3” by 10” and very thin so they will go into most project bags easily. There are two rows of ten buttons each that can be used to count up to 110. I use the top row for tens and the bottom row for ones. The cards are made of thin plastic with a cardboard backing. They can be bent if you, for example, sit on one. However, they are very brightly colored so they would be easy for a low-vision person to see.
As for durability, I would say that, with care, they would last for a very long time. Now, if you compulsively press and un-press the buttons while talking on the phone, the plastic will break down and you’ll have holes where your buttons should be.
I like using one of these as a row counter. They are easy to lay on the table or couch and mark each row with just the press of a button. This can be done one handed so there is minimal interruption to your knitting or crocheting.
I would recommend these to anyone looking for a convenient way to count rows without a lot of hassle. You can find these score cards at APH and they are two for $15.
For other row counting ideas see Ana’s post, Asking Stitchers and Counting Rows
crystal
Ana
Working out Kinks and Fingering Yarn 