Anyone using the older 8 x 3 setups out there have problems getting it repaired on the road? Do you carry specific spares (friction shifters for example) just in case?

Just noticing how inexpensive setups can be obtained used around town for 100 to 200 in reasonable shape. Would try to repurpose an older drivetrain to a franken bike for a teen who is starting out touring. Nothing fancy, just cheap to start out with (ie, like a rigid mtb conversion). 350 buck budget.