The seat may seem a trivial item compared with buckets and backhoes, but the New Warranty Seat thread is the most viewed and most replied Kubota thread on TractorByNet! Complaints about older seat designs persuaded Kubota to issue a new seat under warranty.
Comparison of new (on the left) and old (on the right) seat designs:
Another design not quite as old, but it gave the rider the feeling of sliding off:
Loose Seat Nut / Missing Spacers
Watch out for the central seat nut becoming loose - at least on a BX24 this has hit a few people. When it comes loose, some other pieces (spacers/steel bearing balls) can fall off. Left to go unnoticed, you will lose the nuts and the seat will come off in your hand when you rotate it to use the backhoe. Here's a discussion. [TBN] Where are my seat spacers (BX24) ?