Ask whether a supported upgrade exists
The starting question is whether the existing door has a manufacturer-supported or otherwise properly documented approach for the required upgrade. A collection of generic braces should not be represented as a verified improvement merely because the door looks stronger.
Account for the complete load path
DASMA warns against improvised reinforcement and notes that an upgrade can involve springs, hardware and supporting track. Ask what the proposal changes and how the surrounding opening is evaluated. Leave this work to appropriate professionals.
Compare the finished result
A replacement proposal and a retrofit proposal may retain very different parts. Compare their documented scope, remaining components, project requirements and future service identification. Avoid deciding solely from the number of reinforcement bars shown.
Your questions
Can I add boards or steel angles myself before a storm?
Do not improvise reinforcement on the installed door. Added weight and unsuitable attachment can create hazards without establishing the required performance.
Does replacement always make more sense than a retrofit?
That depends on the identified assembly, supported options, condition and project requirements. Ask for the reason behind the recommendation.