Do I have to replace old electrical?

[Robert Obniski]

I look at a property today that was perfect. 3 beds 2 baths not everything in my criteria until I got to the fuse box. It has old electrical throughout the whole house. It was kind of a deal breaker for me being as I would not be carrying any walls down anyways so the electrical wouldn't be touched. My question is if I purchase and renovate the house, do I have to put in all new electrical throughout the house? To bring it up to code.