I have an LX188 that my dad bought new in 1997 and it is still going strong. The plastics are definitely not the same quality as the rest of the mower. These were only available from John Deere dealers......not the big box stores and that's why they run forever. I recently replace the upper hood and now am going to replace the lower hood. My dad passed away a year ago this month so I am going to keep it going as long as I can in memory of him.
It's getting harder and harder to find certain parts because they are being discontinued so I hope nothing breaks that is critical and can't be replaced. These were over $4,000 new my friend so in my opinion you can't go wrong putting some money into it since it was free.
I have a second LX188 that a co-worker gave to me because the governor messed up and he didn't want to pay to have it fixed. It's a discontinued part but if I can find one I will gladly buy an upper and lower hood for it too (about $300). That's how much I think of these mowers.