Having once had to regenerate 600+ self-signed certs, test that everything still worked, and then insert them into the 600+ live app servers without breaking an

Having once had to regenerate 600+ self-signed certs, test that everything still worked, and then insert them into the 600+ live app servers without breaking anything, all within a two week window because no-one had realised the 10 year expiry was just about to bring everything down, I concur.