We used them for awhile, had few general things that changed over time depending on the issues we were having. Some included eating meals nicely, tidying up, no hitting/ kicking.
Then if they got a certain amount ticks at the end week they got a small prize, things like a kinder surprise or little bottle bubbles. We did find it helped with the behavious and also after time it sort of became routine.
Now we don't need to use them as they know the routines, for example when dinner is nearly ready its time to start packing up their toys.