We have like 8-10 service accounts that require their passwords to be rotated every 90 days and I don't like doing that by hand. 
The passwords had to be kept in a simple format with randomly generated numbers as well. 

To reset the passwords, i wrote a simple script to do it:
https://github.com/MoebiusZero/Scripts/blob/main/Powershell/PasswordResetter.ps1

Because all the service accounts start with the same name it's easy to get them with Get-ADUser. 
With a foreach loop, each account will get a new password and the information will be sent by e-mail to whoever you want.
Within the loop using a switch statement it can be matched to specific account names so you can configure it to send e-mails to different people for each account.
To catch any stragglers that do not match with anything, the default statement is used to catch it.