As other comments have pointed out, there’s not a lot you can do if the technical person wants to bring the house down. But there are other cases you should co

As other comments have pointed out, there’s not a lot you can do if the technical person wants to bring the house down. But there are other cases you should cover against, like the techie getting run over by a bus. The first thing that comes to mind is to make sure you have an admin account and/or a recovery procedure (a master password printed on a piece of paper in a safe, access to the account’s email address to reset the password, etc.) for everything. Everything in this case is at the very least: AWS account (including the root account to manage the bills), e-mail provider, Gsuite admin rights, whoever you brought your domain names from, Dropbox, bank/PayPal/Stripe, GitHub/BitBucket, your telco, the admin accounts on your corporate PCs, and just about all the services you use on a daily basis. The email accounts and DNS are IMO the most critical; you can retrieve a lot of stuff if you control the e-mail or the domain name. BUT this assumes the accounts were set up with a corporate email, which may not be the case if you’re a small company - probably a personal e-mail was used to register the first services, which are also the most crucial. And if the techie knows what she’s doing, she will have enabled MFA, so e-mail alone probably won’t cut it. Just ask yourself: if the tech person dropped off the face of the earth, what would you be locked out of?