When should I remove data from old host after completing the migration process?

Yesterday I manually migrated my website to another host. As my domain is in another company, hosting is in another and I wanted to move the hosting to another. So after transferring the data and updating the name server, my website is working fine as I've started receiving requests in new servers. Now I want to know when I can remove data from my old host and should I need to install WordPress on my my new host. As I moved it by copying all data and making folder by the same name to new host. Please help me on this.

Hosting was done manually