I make these shirt protectors for my BFF's DH, who is in a rest home. You can search online for free patterns. There are a ton of them available. Here's one that I use:
www.fishsticksdesigns.com Click on Tutorials and go down to "Bibs in All Sizes" I use velcro instead of the snaps. They are so quick and easy to make. They are so appreciated by the residents and the staff.
Please prewash your fabrics and use something that can stand up to being washed with hot water.