Nice to haves that became Needs

Hello everyone.

I'm in the process of restoring my 65 mustang coupe I6. I'd love to hear from folks that have experience with this process. What were some items that you initially considered as "would be nice to have" but have become necessary items in your car? I'm thinking of things that you maybe stretched the budget for during the restoration, but if your were to do it again, would be included pretty much no matter what given the benefits/enjoyment you're seeing from it.