Why did you (not) trademark your game?

Hey everyone,
I've been working on our game for the past year. We've been using a working title as we don't have a tentative title yet. A lot of people (not in the game industry) recommend us to get a trademark. We're just wondering why some of you did or didn't do so, and how you reflect on that choice.
I'm not experienced in this market so your thinking process and experience will really help me out. Any feedback about this issue is interesting to me so don't hold back.
Thanks for reading my post and thanks in advance for replying,

Arjen.