Yes, previous use of a brand before being trademarked can help in many cases, most notably in jurisdictions where the first person to use the mark gains earlier recognition in granting trademark rights, such as in the US. In countries like the UK and the EU, previous use can be utilized if the IP Office raises an issue of confusion related to prior filed similar trademarks.
Previous use can also be used in the case of invalidation of a trademark that is not being used and during opposition proceedings.
Ahead of utilizing any of the above-mentioned strategies, you should consider how long you have been using the brand and how well you are recognized as being the source of goods and/or services belonging to the brand in the customer's eye. In order to prove prior use, yearly marketing spend and revenue will have to be provided in order to justify your claim for a trademark.