Playing games with lots of rules is a fun way to train your dog and exercise her mind. (dogstardaily.com)
You will find lots of rules of thumb but there is no universal truth to how much you should save. (money.stackexchange.com)
There are lots of rules in life, the law of the land, doctor's orders, guidelines laid down by management at work, professional ethics, etc.. (nakedpastor.com)