the parts on the deck can vary in how long they last. The idler pulley bearings can wear out with no notice, just spin them to see if you hear any odd grinding noises from them or if they feel hard to spin. If so, replace them. The mandrel housings will be the biggest problem. They have steel bolts tapped into the aluminum and usually the bolt head breaks off when you try to remove the bolts. If they break, you will be wasting your time to try and drill out the broken pieces.
Honestly, if it were me, I would replace the entire deck assembly (164963 ) rather than just the housing. It's about $200 more, but it's a 20 mins deck swap and cut grass. If you have time, take your existing deck apart and determine what all other stuff you need (bolts, mandrel housings, bearings, ect) if it starts inching to around another $100 in parts I would say go with the complete deck and be done with it. If you can take all the old stuff off the existing deck to be re-used and it's all in good shape..and you have the time (about 2-3hrs) then just get the housing. Not trying to scare you into buying a higher dollar part, I just want you to realize all the options.
If you have any other questions, hit me up and I'll be glad to help out.