Baked data 'not exact since frame -1' When I set simulations(tried smoke, rigid body, hair dynamics, and cloth so far) to start at negative frames, I always get this message above the bake buttons:

There's also a gap in the bar on the timeline at frame 0, which I assume is the cause of it:

Would it be better to start simulations on frame 1 and offset the rest of the keyframes instead? Or is there a way to get blender to bake frame 0? Or should I just ignore that message?
You could answer the question if you should &quot;just ignore that message&quot; by yourself: Does the simulation / render looks as expected or at least is the result good enough for what you're looking for? Then ignore the message.
Apart from that, the Blender Reference Manual says the following about baking in frame ranges and offsets (this is in the Fluid section, not general), which suggests baking from frame 1 on and use the offset afterwards: