We had a panther, although we never left him alone without food for much time. My friend had some jacksonii for a while, and I know they went at least a week on one occation, but I also know they were watered during the time.
Veilds are able to deal with drought better than most animals, they can also deal with exttreme heat, cold, lack of food, and variations in climate.
Smaller animals, especially younger ones, but also smaller species, have less body mass, and therefore less reserves. They cannot go as long without food.
If at all possible, have someone feed and water your animals at least once while your gone for a week or more. If, by some way, it is impossible to have someone care for your animals, feed them and water them well for several days, then they will be fine.
My Standing's day geckos have gone through some really tough times. My brother had lost one, a female for about 6 months. turns out she was in an old tank, under the newspaper, no food, no water, for 6 months during the winter. She had not lonst much weight when we found her, and she produced a bunch of babies that year. We've had her for over 10 years, and she was fully grown when we bought her. She's still going strong, and she has producedseveral clutches every year, since we have had a male.
Reptiles are not like mammals. While it will kill a small mammal if they don't eat every day, a reptile can go days with no adverse effects.
However, this DOES stress the animals system, the degree to which it does varies on the species, the size, and health of the animal. An adult veild is absolutly fine after a week of no food or water(provided it isn't TOO hot and DRY).
I know for a fact that deremensis can go without food as long as they have water...My male didn't eat for 2 months after he matured--drove me nuts.
He did die, but that was over a year later, and he was eating at the time.
This is what I do when I go away:
I feed and water a little more than usual for the prior week. I refill my humidifier, and set it on low, so that it lasts all week on the timer. I fill a bowl or two per cage with superworms and a carrot. Superworms last for weeks in a bowl, the carrot stops cannabilism.
I fill a small bowl with water, set it in the branches, stick a few plastic plants in it,and stick an air hose in. The veilds will usually drink from the standing water, but most of the other ones don't, hence the air pump.
I would be more careful with smaller species, and young. IF you have babies, try to pay off a friend.