Rider #1 whom we shall call "Bombshell" is in excellent shape, 29 yrs old, and doesn't know how to ride a bike. (I'm not kidding) Is tired of running and would like to ride every morning maybe 7-10 miles. Will probably ride mostly pavement with some dirt or gravel consistently thrown in. May use it for light grocery shopping.
Rider #2 whom we shall call "Hottie" is in decent shape, 30, also doesn't know how to ride a bike (or has forgotten) and wants something to ride along with the kids on bike paths, the park, and around the neighborhood.
Rider #3 whom we shall call "Casey Jones" is 30, in excellent shape, and is looking for a new bike. Wants to take it everywhere from rides at the park with the kids to 25 miles rides to beat previous best time. Will definitely see some gravel and dirt.
Riders #4 and #5, whom we shall call Bozo (30) and Liar (44), are in the best shape of all, ride bikes, and want to do mostly pavement with occasional dirt and gravel thrown in. 10-20 miles would probably be a common occurrence for them.
Hence, that is why I said "they". I've become the "expert" since I just bought a straight road bike last month, though I know nothing about non road bikes. (but I'm learning)