Advantages to keeping old road bike after getting a new one? (medium-length)

[jobob]

What are the advantages of having a second road bike?

Ah, I see you already have a bike for commuting. OK, scratch that reason.

Off the top of my head ...

It's great to have a second road bike if your primary one is in the shop, or for some reason cannot be ridden at the moment. -- like, it really needs to be cleaned

You could use it as a loaner bike, say if a friend wants to give biking a try (assuming of course that your friend is about the same size as you).

If you have the space, you could hook the second bike up to a stationary trainer and just leave it there for the most part, which is very convenient during the winter months especially.

That's all I've got None of them are really "musts", just niceties.