1. Stuff... Seriously anything from other stuff in game to just being afk in game while doing stuff that isn't FFXIV
2. Pretty much always. The only times it gets boring are caused by other players either causing wipes so we have to repeat the same fight 10+ times in 1 duty such as bad runs on hashmal or the long sessions of blame game finger pointing because of a wipe.
3. Pretty much each content update they attempt to add something
4. Playtime varies on numerous factors
5. Major patches are usually quarterly

Current activities considered endgame. Deltascape savage, bahamut ultimate, shinryu EX. Some may also consider expert roulette duties, susano, Lakshmi, and rabanastre end game as well.

If you manage to get a house atleast decorate it :P