Almost anyone should be able to figure out whether they have an extra $10 or not. If they cannot figure it out, then they have to figure it out...so once they figure out that they have an extra $10 they can get started, and they can sort out the other aspects of their potentially messy finances and/or psychology as they go. Position size can do a lot in terms of both starting out and also not overdoing it so that there are abilities to figure out an appropriate level of aggressiveness. I would thing that most people are going to start out investing into bitcoin in a non-aggressive way and work their way up towards being more aggressive, unless they happen to already have a pretty good grasp on their finances and they can understand and appreciate the strength of bitcoin's investment thesis from the start.
$10 constant investment will amount to little in the long run and almost a messy way to start up a bitcoin investment, I think also that for anyone to arrive at a successful investment position one needs to be aggressive a bit, at least that will help us to be able to take some aggressive financial decisions that can help us to arrive at a good investment position faster.
Investing a low amount like $10 as mentioned by members sounds like a joke considering Bitcoin's current value.
Starting a bitcoin investment with $10 isn't a bad bet, no one is saying to stay at that price indefinitely, and also JayJuanGee said 'extra $10' making that price at the very least the lowest anyone who what to invest in bitcoin should go, if at the end of the day your discretionary only amounts to $10, then invest it! while at the same time looking for ways to increase that minimum. This way a person can avoid procrastinating on when to start investing simple because they can't afford to do away with more than $10 at that time.