Pins that aren’t performing well, or not receiving as much engagement, will not hurt the performance of your other Pins. One dud Pin might have a hard time itself, but it’s not going to bring the rest of your Pins down.
Keep in mind that underperforming Pins could potentially become popular in the future, so deleting them also deletes the chance of this happening. It’s more important to spend your time reviewing your account’s analytics to discover what type of Pins is working well for your audience.
I personally do not recommend ever deleting your own Pins – but I find taking the time to go back and assess Pin performance is time well spent. I also delete my saves of others’ Pins at this time. I won’t do this going forward..