I just planted my first herb & veggie garden about 3 weeks ago.

they will not survive for that length of time without water

You will want to water your new plants, depending on the local weather. Imposing on a gardening neighbor, with the promise to return the favor would be my choice.

If in pots, yes you would need someone to come in once a day to check. If in ground I would still get a neighbor to check every couple of days and water as necessary. Watering twice a day seems a bit much, but it depends on how much water they were actually receiving. Either way, I would get a neighbor to check, bring them a nice gift to thank them.

It depends on how dry and hit the weather is. If the temperature is 60 degrees or less than a once while your way should work. If the temp zooms up to 90 then they do need water once or twice a day.

Check the ground and see how it is holding moisture, most gardens do fine with once a day or less. (Overwatering can cause root rot and mold.)

So so the real answer is "it depends".

Better to have someone check on the moisture level. The first few weeks after planting are the most important.

Or you could sink plastic bottles in the soil. Put tiny holes in it then bury it. Leave the mouth exposed so you can fill it with water. I travel for work and I don't really have neighbors to water for me.

if it's been in for 3 weeks, it SHOULD be ok for a week, just water well before you leave and make sure it's one of your first chores when u return!

Also, you shouldn't have to water twice a day unless it's super hot outside

The best way to tell how much water your soil holds is to dig a hole maybe 8-10 inches. If it's moist then you dont need to water. Stick your finger in the dirt under a plant and feel it. The best advice I ever got for watering- plants like their soil like we like our cake! Moist, but not wet