Its important to read the bounty rules before participating in that bounty. They might have some rules that will prevent you from joining or probably not following them will lead to loss of funds at the end of the period.
When choosing a Bounty project, it is important to carefully study the ICO itself. Working on the first site that promises maximum pay is at least not wise.
Sometimes, people work for 1-2 months but do not receive the promised money. The rules of Bounties must be read as breaking them, you risk not to get an award. If a Bounty participant violated the rules that the creator of ICO found, he may not get anything.