If I make a hard save, are there any risks if I keep saving over that one rather than make a new save? Can someone clear this up for me? Does saving over one save cause more savefile bloat?

I'm not exactly sure, but I don't think that it may cause more bloat than usual saving in new slot.

The thing is - you risk that something goes wrong when saving... One save - you lost the whole playthrough when something goes wrong. If you use Streamline to make multiple saves (with only remebering feature - NO autosaving!), you only loose one save if something goes wrong when saving. And it happens...

Yeah I do keep backups, I meant more in terms of how it affects the stability.

It is generally safer to make a new save. The point to remember is the trade off is "disk space" versus "recoverability" if the save file becomes corrupt. Multiple save files give you more prior points in the game to revert to if needed. If you start to run out of disk space, you can always manually delete older or unneeded saves.

Speaking in general terms, when you "reuse" a save slot, the game merely appends new data to the existing file. When a file is "created" it is assigned a number of fixed size "blocks" of disk space, and adds new blocks as the allocated ones become full. The potential problem is that the "older" version of the file probably (as in "usually") didn't completely fill the last allocated disk block, leaving "filler" of an unknown nature at the end. Appending adds the new material at the end of the old material, based upon the byte-count recorded for the length of the file, updating the file length and overwriting the "filler". (There is more complexity I am skipping over here.) Creating a new version of the file means it gets a new allocation of disk blocks, usually in a different physical part of the disk.

Normally all works as it should, but in the old days of DOS and the FAT file system, the byte count of the file length in the "File Allocation Table" (FAT) might be off and some of that "filler" read in. These days the NTFS file system is more commonly used and is less prone to the problem.

But all hard drives have the issue of a disk block "going bad", meaning it gets magnetically weak and can lose/flip bits. This is what the "chkdsk" (drive "properties" | tools | error-checking) tool looks for, along with inconsistencies in the FAT such as the length of file byte count compared to physically on disk. Unfortunately most people seldom run "chkdsk" so weak blocks and incorrect file lengths creep into the system undetected. It's because this does occasionally happen that it is considered safer to create new saves instead of reusing.

Best practice is to always run "chkdsk" after your system unexpectedly shuts down or reboots. You should also consider doing so if you get a CTD, because there is no telling if the program (game or app) was writing (or caching to write) to disk at the time of failure. A reboot is always recommended in the case of a CTD because the system memory is in an unpredictable state.

-Dubious-