Heat shrink tubing can expire. Please check with each individual product for expiration dates. It is also important to adhere to any storage recommendations such as temperature, humidity, and avoiding sunlight. Below are some references:
https://www.digikey.be/htmldatasheets/production/1778716/0/0/1/fit-reg-shelf-life-guide.html
https://multimedia.3m.com/mws/media/356317O/emd-product-shelf-life-and-storage-statement.pdf
https://www.panduit.com/content/dam/panduit/en/products/media/7/87/387/1387/101111387.pdf
https://www.panduit.com/content/dam/panduit/en/products/media/2/12/012/0012/110090012.pdf