I'm doing bounties and I just allocate 2hours max for the 15 ico project I'm involve with. I have a spreadsheets and there I just open each social media link and listed task I do. Bounty hunting is similar to my job as social media manager so I'm able to apply my skills on it.
So that two hours, is it worth it? Yes if you get the reward and well, charge to experience if you're not rewarded aka forgotten by the team. I learned during my early days in bounty hunting the risk involved so I just doing this for investment hoping the project I'm involve with will succeed. This is also why it's very important to do some background check with ICO you're going to participate so as not to waste your time and minimize the chance of not being rewarded.