A-1 visas are valid for 3 years, and are apparently extendable for an additional two years (allowing one to stay in Israel on such visas for a maximum of 5 years). According to AngloList (http://www.anglo-list.com/aliyah-information/israel-visas?id=625), one must apply to get their extension before the 3 year period is over. However, the criteria that makes one eligible to extend their visa to 5 years is not specified, nor is it specified how far in advance one must apply, nor where one is to go in order to apply for their extension. What are the regulations about this?
As I read the formal procedure for handling Aleph-1 (א-1) visa applications, it seems that there are no extra requirements for extending the visa to the maximum of 5 years; you will need to apply for the extension using Form Aleph-Shin-Slash-3 (אש/3).
Caveat: I have never done this myself nor do I have acquaintances who have. I merely read what the ministry writes.
Obiter dictum appeal: Please consider carefully the moral and political implication of using the privilege of people of Jewish descent to immigrate to Palestine/Israel from anywhere in the world (which is what א-1 visas are for), while the native Palestinian population is mostly stuck outside of their country as refugees after having been driven out in large numbers in 1948, and in 1967.