-Shin guards - 1 year
-Helmet - 1 -2 years if treated well. The usual issue with the helmet is missing parts due to the user's inability to locate and use the correct screwdriver to keep stuff properly attached/tightened.
-Chest protector - good as long as it still matches the helmet and shin guards
-Gloves - 2 - 4 years if treated well. A catchers glove that "looks good" maybe past its useful life if it is loose and/or floppy /streched out etc...
right now my mitt is 5 years old and is still as good as it was the day i got it (just broken in now lol)
and all my other equipment is on its 3rd season...
....i usually play about 75 games a year and so far all the equipmetn has lasted
My 15 yo kid had 3 sets. Youth until 11, intermediate until last year and now adult with nocsae chest protector. The y and int sets are I. Good shape considering how much he abused it and barely took care of it. He is still using hockey mask for both comfort and hs requirement, I ordered the force3 defender for the better shock absorbing face mask. It is heavier but the kid not mind it after taking a direct shot with an 85 mph ball and only had ringing ears.