Doesn't really matter, nor do plans on having a camera a very long time matter when buying used or new.
I've used both wood and metal over the decades. Each does the job I've asked it.
You must discern from your shooting style which is best for you. Ask 10 people and your'll get 10 unique perspectives.
Right now I have a metal 4x5 and a wood 8x10. Both are perfect for what I do, but that does not answer your concerns.
Best to try out both styles in the field. Road testing is the best solution.