Synthetic vs Real Dreads

When I do get the synthetic dreads and attach them (I don't have natural dreads yet) I read that keeping them in longer than usual can cause your hair to start dreading on it's own, is that true?

My personal experience is that when I have left the dreads in for 4 weeks or more my hair had begun to dread naturally. That being said, I would just use a healthy amount of conditioner and the dreads would naturally unravel. I would assume that there is a way to encourage the growth of those dreads to continue. Since that has never been my goal, I have no experience or knowledge to share on it.

I'm debating on whether I want to dread my hair now and add synthetic or add the synthetic and continue the dreading after.
Well, I guess that would be a personal choice. If you've never had dreads then synthetic dreadlocks would allow you to see what having dreads is like and give you the immediate gratification of having them right away. You could then take them out and start up your own dreads. Remember, your hair will be a couple inches longer then. Then, you could always put the same synthetic dreads back in your hair!

Sorry for all these weird/dumb questions.

Not weird or dumb. Rather, they are perfect normal questions to think about when considering dreads and how you might want them to interact in your life.

I just don't want to spend a ton of time, not to mention pain in my arms, dreading my hair if it will start naturally with the synthetic.

Oh, well... then I would go with synthetic first. :-)