There's a fine line between 'not enough' and 'too many' email sends to your prospects. The goal is to send enough emails to keep your prospects engaged but not so many that it would risk your prospects become irritated or see the emails as clutter.
Unfortunately, there's no one-size-fits-all solution here. The ideal send frequency has been debated forever and will likely continue that way. You should always be testing to see what cadence works best for your company!
So what can you do?
Setup Email Send Frequency Cap settings within your respective email sending tool or marketing automation platform, which will allow you to set the maximum number of emails every contact should receive in a specific time-frame.
EX: Settings ---> Marketing ---> Email ---> Send Frequency
Have a critical email or autoresponder that needs to go out to everybody despite the frequency cap safeguard? That's okay! You should have the ability to disable the email frequency cap for specific transactional emails!