As in most ports of entry, customs authorities man both red channel and green channel exits from Israel's international airports. Go through the green channel, unless you have something to declare.
If you bring into Israel electrical appliances with a value of more than $200 - not what you paid for them, but the value according to customs officials' lists - you must declare them and you may be asked to pay duty. If you have an invoice on which the value of an item is lower than the one on the price list by no more than 20%, the price on the invoice will be used for the purpose of calculating custom dues, and not the price list.
The specific procedure has a couple of variations. Tourists arriving at Ben Gurion will list the items in question on a form and will leave a credit card imprint on which the sum is listed that is equal to the required duty. (A deposit in cash is one other option). Upon departure, the credit card slip will be destroyed when proof that the item or items that had been taken into Israel, have not been left there.
For flights into Eilat, customs authorities will ask you to sign a declaration stating that the items will return with you when you leave. Here too, customs officials will probably want you to show them that you are taking all the items listed in the declaration, with you.
Current duty-free allowances for everyone entering Israel are: 250 cigarettes or 250 g of tobacco products, two liters of wine and one liter of spirits, plus 250 mg. of perfume.
Agricultural regulations forbid people from entering Israel with animals, plants, firearms, fresh or meat.