Carrying spare bearing question

I just lost a bearing. Outer race seized on the spindle. I was fortunate to get parts easily. 3 hours later back on the road. Now if I had the spare bearings, seal, grease and some fine sand paper I'd have been back on the road in half that. I'd have also needed a washer and retaining clip. Cause for failure? Missing retainer allowed the castle nut to back off. Not happy that the dealer I just bought from used doesn't check bearings as part of their standard inspection. And no, I won't name them as they handled it very well and I believe changed their policy since.

Moral? I'll be carrying spare parts starting next season.