A case in point is my 72 Lejeune. When I acquired it it had a 52/40 cottered crank on it and a 14-28 5 speed freewheel. The Simplex FD was cracked and I was going to upgrade to cotterless anyway so I acquired a 52/40/32 triple crank/chainrings, a FD that would handle a triple, and another spindle. Put it on and found out for my everyday riding I could go to some smaller cogs on the back. So I acquired 2 more freewheels on ebay for around $15 each. A 14-24 and a 13-21. Now I have the 24 on for my everyday riding. If I'm doing a flatland century the 13-21 goes on. If it is some loaded touring or really hilly riding the 14-28 goes back on. I can take the wheel off, replace the freewheel and have the wheel back on in about 5 minutes. Same chain, RD and best of all tight gear spacing. It works for me.

Of course if you get a modern bike it will have all the range you need. But where is the fun in that?