Naming Rights and Trademarks - how important really? I will not promote

I've read some horror stories about missing Trademarks and the Company was forced to remove their app from the official App Stores, just because someone registered the trademark and filed against you. However, as someone bootstrapping filing for Trademark in the big markets like EU, UK and US for company + app is already quite expensive and maybe can get up to 10k USD, depending on the number of classes. Do you have more experiences you can share? How important is this really? Especially if you make your ap