A great tip is to always compare how often you send your clients emails with the amount of unsubscribe you have for that specific period of time. If you see that when you send emails too often, the unsubscribe rate goes up, then that means that they are not liking the fact that you are sending them emails too often, and after a while more and more clients will unsubscribe. I suggest you try to keep your clients by not saturating them with too much information.
As a personal experience, I would like to tell you that I subscribed to receive email from a particular brand that I love, well let me tell you, it was insane, I would receive an email every day, I ended up unsubscribing. So, they would have kept me as a subscriber if they did not saturate my inbox, but unfortunately, they did.
Every time you are ready to send an email blast, make sure that put yourself in your subscriber's place, and make sure you would not mind receiving that email too soon from the last one you sent out. If you think that they will not feel annoyed, because there was a reasonable period of time between the last email and the one you are about to send, then go for it!