Stem Cells can be stored for as long as 50 years or even longer without going bad.
Sperm and many stem cells have been stored for 50 plus years and have remained good even after all those years in stem cell or sperm storage.
Stem Cells and other cells are stored at a very cold temperature which is - 374 degrees F
So that keeps the stem cells in good shape which keeps it from going bad and makes the stem cells last a very long time.
So you can store stem cells for a very long time and they will remain viable for 50 years plus.
The stem cells may also be stored over 100 years or longer but as of now there have not been any stem cells that have been stored that long.
100 years is a pretty long time.