Funny that you asked. I just got 30 fixed. My parents told me me that in 2013 they got ARM at 3%. Thankfully they were able to payoff the house before it. Out of curiosity i looked up the difference between 3% and 6% on my mortgage. It's over $1000. Whether you are comfortable with huge rise in monthly payment, it's up to you. Obviously after some years you would have paid of some of the loan so the jump wouldn't be as drastic. What was much more interesting is searching ARM on r/personalfinance. 2-3 year ago, we got lots of comments how the rates will never go up.

I don't know what the common wisdom is. I know that if i were to go with ARM, I would run some more math. Personally, i don't believe when people say "you can always refinance". I was told that by many. What i do wonder is what can I refinance to? When will i look to refinance? Will i look to refinance when rates are going up? Will i look to refinance when the market is in a "gully"?