Update 2:
I noticed this was coming up in the chat fairly often but not as frequently:
The errors listed in text form for posterity (mainly search results):
Server Save Failure: HTTP (500): Internal Server Error
Error: could not upload place. File too large
Server Save Failure: PublishService AssetUpload failed. Info: UploadStatusPolling max polling retry reached
If you download a copy of the place, what is the size of the file created?
Some posts I’ve seen suggest that the size limit for uploading is about 128MB. Is your file around this size?
I would’ve loved to have known this; yes we have gone past this file size.
This isn’t going to recover your lost data (ran into an even worse issue years ago), but I always make local backups just in case now. Ever since I had the issue where I would lose random chunks of my game and then had to spend hours/days tracking down what was lost at random. 
Also, I had no idea there was a file size limit (well, I knew one had to exist, just didn’t know what it was). How big is your game now if you make a local backup?
Currently the file size is 135MB; I can definitely trim it down though so I’ll do that for a bit.
Hi TigerCaptain, thanks for helping validate auto-recovery files.
The original issue was that the place file was too large for save and the error was not descriptive in the Output logs. We fixed this to be more descriptive hence the Output logs now show a better worded message “File too large”. We believe we can do better here, and have a couple of improvements in progress. But until then we recommend keeping the Output logs tab open to track save issues.
One thing you could do to get the place file size down is to set the collision fidelity on all of the mesh parts in your game to box or hull.
We’ve been repeating for years now that printing critical feedback messages to the console is wildly unacceptable; it downplays the importance of them, hides them from the user, and causes accidents. Studio should have the capability to throw toasts or dialogs for information that absolutely needs to be seen by the user. Is this finally enough lost work to have a solution prioritized?
Yes, this, it’s also worth noting that many developers (especially non-scripters) do not enable the output in their view and hence will never see these errors.
I spent a good amount of time trying to find some “official” answer on this and I find answers ranging from 100MB to 1GB, so basically no one really knows. 
I read about someone that published a game with a 156MB place size, etc. Basically years of people bumping into this limit (whatever it is?) and posting here about the issue without any help or solution.
I have to ask, why changing the setting on an object affects the binary file size?
I am unable to find where the official place file size limit is documented, is there an official limit? The forum is full of post where users claim the size limit is all over the place, some even claim up to 1GB in size. 
Final update:
The main culprit was a team member’s plugin (3D text) that inserted copious amounts of meshes that had Archivable set to true. Every time this member joined team create, the plugin would re-add every font + letter combination in its library, and each one was a mesh. This essentially caused the file size to get up to 230MB file size at one point.
Since then we removed the plugin and removed the added meshes + duplicates, and the file size was reduced to 30MB.
I have to ask, why changing the setting on an object affects the binary file size?
As part of optimizations, there are items that are pre-computed. The pre-computed data may have an impact on the size.
I am unable to find where the official place file size limit is documented, is there an official limit? The forum is full of post where users claim the size limit is all over the place, some even claim up to 1GB in size.
The official statement from this post is still true unless we make a future official post. Here
Anything above this limit may work but it is not guaranteed to not run into issues.
We’ve been repeating for years now that printing critical feedback messages to the console is wildly unacceptable; it downplays the importance of them, hides them from the user, and causes accidents. Studio should have the capability to throw toasts or dialogs for information that absolutely needs to be seen by the user. Is this finally enough lost work to have a solution prioritized?
and
Yes, this, it’s also worth noting that many developers (especially non-scripters) do not enable the output in their view and hence will never see these errors.
We agree with you here and feedback is received. The solutions we are looking at are ways to elevate certain passive messages and also errors out of the console log.
Wow, the old limit was 4MB that recently? 
Ok, thanks for finding that. After reading about +50 search matches, I just kind of gave up. 
So 100MB is the recommended limit, but you might be about to squeeze more in, interesting.
For future reference should others come read this, here is a simple test I did. I yanked 252 tank models out of the toolbox and pasted them on a new baseplate, then exported the place file. Just with the default collision settings, the file size was nearly 3MB in size. Then I changed the collision to “box”, did an export, and wow, the file size is only 82 KB now. 
This is good info to know for the future.
Given the wording of that post, it doesn’t appear that the limit was actually 4MB but rather that the limit for OpenCloud was 4MB, while Studio (likely) allowed you to publish larger files. As mentioned in that post, OpenCloud was later increased to 100MB file size limit. Are you sure the manual publishing recommended max file size is somewhere around 100MB, or is there no official statement on recommended max file sizes other than max sizes for OpenCloud?
The recommended sizes between Open Cloud and Studio are the same at this time.
