1. How often should I vote? Once a week? Once a month?
Why should you? If you already have a list of delegates you like and all your
stakes is in some way voting for your favorits I see no reason in a 'regular'
voting
2. Do I have to go and manually do the above operation of voting every time
(choosing Vote as Delegates recommend. My whole BTSX balance being sent to me
and a fee of 0.5 BTSX being deducted) or can I program a client do this for me
from time to time?
No .. voting is performed automatically when you transfer BTSX .. The point of
the "vote now" button is just for convinience if you really 'need' to vote with
your full power just now.
3. Even after I voted, I still have a small triangle warning about the not
voting with all stake or something like that. Did I vote right or not when I
still have this warning?
As far as I know (not sure though) is that you need to vote for >101 delegates
with ALL your stake for that triangle to disappear.