The statute of limitations isn't the only reason to get a head start on your case. The more time passes, the more difficult it can be to access and gather evidence. For example, witnesses may start to forget crucial details of the crash over time or move away without leaving any contact information. Businesses may destroy video footage capturing the collision after a few days or weeks.
Evidence like this can help boost the validity of your claims, and not having it can make it tougher to prove your side of the story.