Is it important to manually clean your Blueprints after finishing them?

I am talking about removing the excess nodes and events that arent even used.

A node that doesnt have pins connected doesnt get packaged as far as I understand, so they should be fine, but what about long line of nodes connected to custom events, -events that are never launched? I make many Blueprints by duplicating the existing ones, and altering their uses to the needs of the BP. Quite so often, these duplicated BPs still contain never launched events or never used variables in them. Like when I copy a level into second level, the level has all the level 1 variables and events left, of which some might still be in the level 2 BP.

These arent causing bugs since they never used, but do they make the packaged files noticably larger for disk space usage or memory requirements?

I would always clean the blueprints, even if the dead Code doesnt cause any problems. Its just a matter of esthetics and I perfer to work with a clean code. But its just my opinion

Probably isn’t going to make a huge difference to the final package size, normally that comes from assets like textures, levels, mesh data, Etc. For me it is more a case that I work with others and I don’t want them digging through redundant scripting. But on a personal level, there have been cases where I have later needed to go back into my scripting to change something. As it has been a while I can forget exactly how things worked. So I always try to make sure I have commented / cleaned the files up more for my own ability to quickly learn how things are working / why it was set up this way. Extra stuff that isn’t doing anything could add in some confusion especially if it looks like a valid custom event… If you do keep it I would just comment it so you know that it isn’t being used, but would suggest just purging it. If it reusable elsewhere and that is why you are keeping it, then maybe set up a blueprint function / macro library to keep it.