Medicated, diagnosed ADHD-haver speaking.

Unmanaged ADHD is dangerous, and incredibly detrimental to people's lives, but the level of such may not be entirely apparent to somebody until after they receive treatment. I think the attitude of being against medication for neurological issues where that is recommended by medical professionals (including where that for something perceived to not be detrimental enough) is, to say the least, risky.

I would perhaps encourage you to do some reading into the real-world ways ADHD affects people's lives beyond just what medical websites say.

To answer your questions, though:

* Medication vs coffee: yes, I don't notice any effect from caffeine

* Meds weakening over time: nope

* Medication cost: so worth it (£45/mo for the drugs alone in the UK) because I was increasingly not able to adapt or cope and continuing to try to do so may well have destroyed me