As it is said in the Tor FAQ: "each Tor client selects a few relays at random to use as entry points, and uses only those relays for her first hop." These relays are known as "entry guards".
I have read many things about this: For example, that "every client picks 3 guard nodes and keeps them for 2 to 3 months". But I've also read that Tor is currently thinking of setting up a single entry guard node (Proposal 236: https://gitweb.torproject.org/torspec.git/tree/proposals/236-single-guard-node.txt).
Then, CURRENTLY, in the version 0.2.9.10, how many 'entry guards' are chosen and for how long are they maintained? And another question: does the "NumEntryGuards" option affect this list of nodes?