Safe to add more mods?

[HeliosPh0enix]

I’m general, how safe/risky is it to add mods to a save game that is already in progress? Are there any specific categories or types of mods that are generally safe to add to a persistent save, or any types that are more often dangerous to add to a current save? I have a 1.4.1 modded career going and I want to browse the mod release pages and add anything that catches my eye as it gets updated to 1.4.x. On a similar note, is it mostly okay to have mods optimized for 1.4.2 or 1.4.3 with a 1.4.1 install, or even the other way around, with mods meant for 1.4.1 installed in a 1.4.3 save? Thank you for any and all replies. 

[Gargamel]

Usually, it is safe to add a mod.  But some mods are known to break ships or saves.  I believe Kopernicus will break all your solar panels already in flight. 

Read the Mod thread thoroughly (or at least the OP), and do search for "broke" within that thread. 

Some mods, like Final Frontier, are underwhelming when added to a game already in play, especially if you are a ways into it.  You lose a lot of the joy it brings from early game accomplishments. 

1 hour ago, HeliosPh0enix said:

On a similar note, is it mostly okay to have mods optimized for 1.4.2 or 1.4.3 with a 1.4.1 install, or even the other way around, with mods meant for 1.4.1 installed in a 1.4.3 save? Thank you for any and all replies. 

Again, read the thread.  Most mods will work in 1.4.x across the board, but some don't. 

[ARS]

Installing mods that's incompatible with your KSP version usually leads to crash (some mods still functions, though) but usually, it's inadvisable to install mods with different version. Adding new mod while having a savegame is as far as I know, is okay

You better not remove a mod (especially if there's an active craft that's using the part from mod that you intend to remove) if you have a savegame, since usually that leads to unforeseen consequences

[Gargamel]

28 minutes ago, ARS said:

You better not remove a mod (especially if there's an active craft that's using the part from mod that you intend to remove) if you have a savegame, since usually that leads to unforeseen consequences

If you install a mod to test it out, don't like it, and don't have any new crafts depending on it, then it's ok to uninstall it.  But ARS is completely right.  Bad things will occur if you remove a mod that is in use.

[Tex_NL]

@ARS Pretty much summed it up. Adding is usually safe. Removing can cause issues.

Apart from that there is a simple 'protocol' when adding mods:

1. Make back-up.
2. Install mod.
3. Test.
4. A. If nothing breaks it obviously works.
   B. Is something does break remove mod and restore back-up
5. Enjoy.

Edited April 30, 2018 by Tex_NL

[HeliosPh0enix]

Thank you everyone for all the responses!