Hello everyone,
and as this is my first ever post, I would like to thank all the community for the help, support, and answers i have ever gotten on sims!

So, here is my problem: I created a city, mostly meant not to be uploaded, but for me to build and play. It took me a whole lot of reading and trying, and after two months, it is almost ready for me to build lots.
However, whenever I try to build, i either get the dreaded infinite loading after hitting edit town (i click edit town, i build, the edit town to save, then loading forever), or the game gets completely laggy.
At first, I attributed it to CC considering i have 7 gb of new cc, but yesterday I built and played with all my cc in a downloaded city. Therefore, it is my city's fault.
If I try to build to from edit in game by CAW, i have no issues. Please advise me!
Should any of you have the time and be in the mood to further search it, pm me with your email and i can send you my city so you test it.
thank you everyone!

What have you done about routing?

The above about routing is really important, before exporting a world make sure to go to View at the top> Rebuild routing data. I've been told it's good to do this ever so often in the process of building up your world.

Here is a list of things that improved things for me in the past, and I had the same issue at one point

1. Convert Sims3pack (Do not do this for world files or any set that contains counters) files to .package files and merge as much CC as possible (KEEP THE BACK UPS! You may later decide you want to get rid of something and without the backups you will be stuck with it unless you're willing to delete the whole file). Before you start the merging process sort your content as much as humanly possible so that if you want to make changes later it's an easy process.
2. Delete you cache files EVERY time you make changes to your CC.
3. Don't go too heavy handed with trees, effects, or spawners.
4. Try re-exporting the world if the sims3pack files seems broken just in case something got borked during export.
5. Also, if your CC isn't merged pull out any CASim content and only build with what you really need and want in your world. Another option is to keep a copy of the Sims 3 folder with a copy of just you buildmode CC inside to make things easier.
6. Don't build for long periods of time without saving. Also, how long are you building for? Long build mode sessions often have bad results like this. Even just using create a style a lot can cause this to happen.. I'd download nraas saver so that you can have a reminder to save often. When I build up my world's lots I tend to slap up the building structure (walls, windows, doors, etc), then do all the buy mode placement, save, and then I go in and start using create a style if I want to, and I still save ever half hour or so.
7. If the game doesn't have enough resources to do what it needs to do this can happen a lot also. When working with CAW (especially the EIG feature) try and have as little going on in the background as possible. Like a browser tab or two probably would be fine, but if you multiples running alongside a bunch of other background program it can eat up the resources the game needs to save and process the changes going on.
8. Personally, I've had really bad luck with the CAW EIG feature, and this is probably how heavy handed a CC user I am myself. One trick I did that helped IMMENSELY was to export my world and only build in the full version of the game, and started regularly deleting excess temp files so my game was running as light as possible on start up.
9. If you are only using EIG, pull mods. I've found I've had much better luck if function mods are removed.

Hope something here helps!

Thank you so much for taking the time for all this advice! The truth is I do all this stuff, and the paradox is i do not have issue in EIG, my problems start when in the normal game i hit edit town to build a lot. I noticed that, irrespective of saving or not, every third time i press the edit town button in order to save a 3rd time, that is when i get infinite loading. Maybe it is a routing issue as I am not sure I know how to properly do it.

thank you for your reply!
I routed before i start placing lots, but I am not sure I have done it properly, as I have read something somewhere about a button in CAW that re-adjusts routing. Would you have more info on this?
Perhaps this is my issue, as the world appears problematic in original game not in CAW or EIG, and as I said below, all my CC is merged in packages and works remarkably fast and smooth in Modern Heights world.
Any advice on routing from any creator is more than welcome!