Generally speaking, you do not need a trademark to use your logo. However, using it without this protection could be risky for a couple of reasons:
- Other brands might infringe on your brand by having a very similar logo.
- You have no protection against someone outright taking your logo and using it.
- You risk someone else registering the trademark for your (or very similar) logo before you, rendering you the person infringing on their trademark. This is a situation you might not know about until receiving a request to cease & desist your brand.
Therefore, we recommend registering a trademark for your logo (or at least the brand name) as soon as possible.
Bear in mind you don't need to be commercially active under the brand yet to register a logo trademark. You can very well protect a future business idea - you just need to be sure to submit a final version of your logo since you won't be able to make changes to your trademark after filing.
However, a special point needs to be made about the United States where if you are not commercially active in the US yet, you can file an "intent to use" application, but you'll have to prove entering and trading in the market within one year of filing, meaning that in the US, it's better to work around a pre-planned brand launch.