It's up to you, but it's only a credit until you pay it. If you just pay it then you don't get charged any interest. Just pay the full amount in direct debit every month and you're not paying any interest. And then you can swap the points for Miles or whatever.
Honestly, unless you are like some of the maniacs here who take out 10 credit cards and use them all to pay off the other, and live within your means (but just using the credit cards as a tool to help you get bonuses) you should be fine.
I don't have the motivation to go find those deals. I'm sure there's probably a website or reddit thread I could follow now-a-days though.
Yup.
A twin stick tranny is pushing it, a three stick set-up is just dick swinging and overkill.
thepointsguy.com is also very good. Flyertalk is more about airline miles in general whereas thepointsguy focuses on the credit card side. Between "him" and creditkarma, it's not tough to figure out which app to do annually. Not even a little.
http://www.carbuzz.com/m/Article.aspx?Id=35572
Halfsies, anyone?