I am a baby on this forum (51).

1. What type of bikes do 50+ folks ride?
Road:
'77 Bruce Gordon (owned since '81 used primarily for commuting these days)
'98 Merlin Extralight (my go fast bike)
MTB:
'99 Fat City Yo Eddy (for playing in the dirt)
Fixed:
'88 Schwinn Paramount - conversion (to learn something new)

2. Do you take any special supplements/vitamins/minerals as you have grown older?
Multi Vit's, Glucosomine

3. How much do you feel you have "slowed down" if any?
It takes longer to recover from hard workouts, injuries.

4. How long have you been biking?
Have owned and ridden bikes ever since I was a kid.

5. What type of biking do you do? Long rides, touring, short rec rides.
Frequent Commuter - 56 mi R/T (I have a very nice route)

Solo rides, rides with friends...

I like to do several organized rides each year. The ones I like best have included rides like "High Pass Challenge" and "Tour DeBlast", "Crater Lake Century", "Native Planet Classic" all here in the Northwest and feature lots of climbing in the mountains. The rides I am looking forward to this year include Mt St Helens' "Tour DeBlast", the "Death Ride" in California and "RSVP" which is relaxed 2 day ride from Seattle to Vancouver BC with my son who is starting to show an interest in cycling.

6. How often do you bike? Your approximate annual mileage?

Approx mileage? Never cared to track. Over 4k? (kept track for a month long "Bike to Work" challenge and logged 1050 mi's in May last year...).
Spring: several times a week
Summer: nearly every day
Fall : several times a week
Winter: several times a month weather permitting. (I prefer to ski in the Winter)