The good thing about the Airtasker platform is that you can be more particular in your posting so that interested Taskers can gauge whether they can take on the job for you or not. The first limit to what errand runners can do for you depends on their ability to take on your task, whether delivery services, furniture assembly, or even concierge services. The second limit is, of course, anything illegal. Check with your local authorities and ordinances to be on the safe side.