How hard is it to have an extra extender on the spare tube?

I'm definitly not a pro, and I train with all race gear except my race closets clothes (i.e. I train with "race" wheels and semi aero helmet).

I don't have any training wheels, and I really want to use my gear, why buy something you only use a few times a years? That's really wasting money 😀

Not hard. But I'm a roadie and often ride with roadies. I like to have my flat changes done in less than 2 minutes so people aren't milling around getting mad at me. If you ride alone, etc, not an issue.

Even if money were no object, I just can't justify banging a set of race wheels or tires around in training. I am admittedly old, train on a road bike a lot and don't hesitate to jump curbs, ride on dirt,etc.. If I had a Ferrari, it wouldn't be my daily driver, I wouldn't drive it in the rain and snow and would worry about potholes, dirty roads, debris. There's a bit of freedom in strong, high spoke count, comfy wheels that are inexpensive to replace. Cycling is one sport where, for the most part, you can go from training bike to race bike, Jeep to Ferrari, just by swapping out the wheels.