Hello everyone,
I was wondering if it would be advisable - because I know it can be achieved without much trouble - do host the wallet files on an external disc drive.
Will it stress particularly the disc drive in question?
Will there be any latency due to this?
Thank you for considering my questions!

Concerning the latency, depends on type of drive that holds your OS. If it is SSD then the change of that factor will be barely noticeable and negligible but if your OS is on HDD then adding external HDD (SSD better yet) will reduce that factor. Regardless, it is always better to keep wallets on external drive as it adds some flexibility to actions in the case your computer is out of commission.