What is worth writing down while solving quant problems?

I used to write down what could cause me to stumble. For example - if it had inches and answer was feet or something else that could "trick" me into answering the question with the wrong answer.

But then "blindly" would end up write down all numbers as it gave me a bit of a break in reading the question (but your experience may vary if you get thrown off track by taking a pause after every number).

I think you need to figure out what strategy of answering quant questions you want to pursue.
1. Read the question quickly, re-read again and write down
2. Read slowly and write down and re-read quickly/glance for traps
3. Optional - pause and do a check at the end to make sure you solved it right/did not miss anything
4. Optional - pause before jumping into reading the question (I used this one as it helped clear my mind from the fog of the last question)