I have been using the same set of Cannondale panniers since 1989, and I am finally retiring them this year. They are just the right shape and size, and attach securely quickly and easily. Last week I bought a set of used Cannondale panniers for $50 on ebay. They are probably 20 years old.

The old ones were trouble free for 15 years of hard use. Once a year for the past three years I took them to a shoe repair shop to get tears in the seams fixed. I sprayed them with waterproofing goop every couple of years as part of regular maintenance.

Sadly I don't think Cannondale makes this pannier anymore!