Keeping both 300's?

I have a very good very sharp a bit beat up 300 f4 non IS - thanks Petkal for this as he strongly recommended this one, and recently just got a f2.8 version.

I haven't taken the f4 out of the bag since and not sure if I'll ever use it. I can see it as a light, small travel lens but if I'm travel and know that I'll need a 300, I'll try my best to bring the f2.8 one.

Does any of you have both and keep both?

It doesn't sell for much now but I can probably get a 1.4x and a 2.0x TC for it or a Gimbal head

If you dont use it, why are you keeping it?

Sell it if you're not using it and not likely to, the money could be put towards something more useful.

Edit: Actually, considering you can afford the f2.8 donate it to a worthy cause... like my bag 'o gear