I'm 70 and started out riding/racing on a 5 speed friction downtube shifter with sewups a long time ago.
My line in the sand is what I can afford, want and justify to my cfo.
I like modern technology and currently ride/race a Tarmac SL8 expert with Ultegra Di2 12 speed with Elite 50mm carbon wheels. I built it and love it...one sweet ride.
I do miss riding my old Colnago, SL tubing but even at a 48cm frame I could rub the front der. when sprinting...it sits proudly on my shop wall with a crumpled top tube from a crash at the nat crit a long time ago.