Do you give advice here that you don't follow yourself?

Depends... had a Dragonite with DB HU and recommended it for Macho Solos, since i Solo him with Alkazam and Espeon i Changed it to DB OR now.

Recommend Blissey with ZH DG, since i have 3 of them i also leave one with P HB

For now i didn‘t TM my Blizzard Kyogre to Hydropump, because i sometimes use it for Ray

TMed my Mew2 from Focusblast to Shadowball when i received my 2nd Ex-RAID-Invitation, my 2nd Mew2 now has Focusblast

...

When I advise to not power up this or that pokemon I feel weird inside because I can never be in a position to give this advise as I am a gigantic star dust spewtard. At level 37 I never had over 300k star dust and I broke 200k maybe 2 or 3 times. Anytime I have dust I have to spend it. I can't control myself. It's weird because in real life I do the exact opposite with my money I try to save as much as I can.

No!
Unless you count past mistakes that I would not do now nor recommend like investing stardust in multiple over 3k CP Pokémon because of how the old gym system worked.

Yes, I recommend people power up multiples of good legendaries, I only power up one legendary per species. Knowing what's good or optimal isn't the same as wanting to play that way. Other examples I guess would be maxing Scizor or Lugia, which I've done but would never recommend anyone else do, or maxing 2 Espeons, which I will do if I ever find a 100% Eevee. I have reasons for doing these things, but they are generally speaking not a good use of resources.

I was very successful gen 2 bc I bought/earned incubators and I would clear out eggs fishing for purples. When I completed my Dex I started putting 10k eggs in the infinite and never using incubators...bought a big box so cleared all my 5k eggs out with the cheap incubators. Better result.

I recommend this recommendation to provide selective recommendations

Oh wait! I do not follow this recommendation myself..

"Don't use metagross and salamence they are garbage"

Both are regulars on my gym team.

No. And because it won't accept such a short answer, I'll keep typing and say that the real answer is "not yet".

Yes, because I try to actually answer questions in a way that suits a player's playing style or will help them achieve their goals. I don't try to force my playing style onto others.