Warranty - How long before it runs out

[dig dug dan]

i did a landscape job for some friends parents almost 4 years ago, and have been back a few times to sort one or two issues,all minor issues, such as a bit of pointing missing, or a loose slab.
Thing is, they have now contacted me again to say a slab is loose on their step.
When do i draw the line and start charging to rectify problems? how long does the "warranty" actually last on a job like this??

[lutonlagerlout]

till the money runs out :;):

joking aside i think 4 years is long enough for wear and tear to have effect

charge them

LLL

[RAPressureWashing]

Family & friends work usually equals PITA, as they always think you are on tap to sort out a/yet another problem.
If it was "Joe Public" how long would you warranty or guarantee your work for? I'd go along the same lines, but that's just my opinion.