As have got 1TB external drive, there is no problem ...perhaps in a decade need to change for a bigger one.
I'd say wait until you get your first problem before you go straight in and download the entire blockchain on one of your wallets.
If you keep the four wallets going in different directories on the hard drive as it'll take only the 10 hours again to redownload everything if there is a problem and it doesn't take up any more than 10GB of space on your drive anyway for the ones that are pruned.
I keep a full updated version of blockchain, it was 5 weeks to get fully download, so I prefer not to download again from "0".