I have dogs and cats so my friend who watches them will also keep an eye out on the reptiles. For the snajes, she will not be spot cleaning or doing anything other than to look into the cage to see if they are still alive; and to do a weekly water bowl refill/clean. For the lizards, same thing except the beardie gets a salad every other day or so.
My local reptile stores can board your reptiles while you are gone. However, I don't like the way they keep the animals (ie calcium sand for beardies), and while I'm not the most fond of vet boarding, I would probably have no choice to board my reptiles with my vet. Outside boarding is the last option if for some reason I must leave them unattended for more than 3 weeks. If I ever have to be gone that long and that frequently, I think rehoming rather than boarding would be for the animals' best interest so they won't be stressed out and consistently moved around.