I would certainly ensure when sending that you are sending to active and engaged customers. For initial big emails, it is often good to send to a larger scale database, ie; All.
However that being said and back to your point, yes absolutely. List cleaning is good practice and great to get into a habit of. There are automated ways you can do this with the Sunset Flow (See this article; https://help.klaviyo.com/hc/en-us/articles/360017518492) and it is also good to create a Win Back flow too, which tries to reengage customers who may have been away from your brand for some time.
Welcome to the Klaviyo Community and thank you for your question!
There is a number of things you can do to improve your Open Rate or CTR - if these are the things you are focusing on. But as they are completely different and require different actions, I think the best thing is to decide which you will tackle first.
Klaviyo is filled with helpful knowledge on these areas.
If you are looking at Open Rate - I would look at your Segmentation (create segments for engaged audiences, audiences who the message is for), send time, subject line and ensure you are using a clean list and also ensure your sender reputation is progressed:
thank you for your reply. Also I have been thinking. What about my customer list? Should I do a deep clean so I do not need pay higher plan and delete unengaged clients?
I would certainly ensure when sending that you are sending to active and engaged customers. For initial big emails, it is often good to send to a larger scale database, ie; All.
However that being said and back to your point, yes absolutely. List cleaning is good practice and great to get into a habit of. There are automated ways you can do this with the Sunset Flow (See this article; https://help.klaviyo.com/hc/en-us/articles/360017518492) and it is also good to create a Win Back flow too, which tries to reengage customers who may have been away from your brand for some time.