I can always tell when I am hypo and " most " of the time when I fall into Mania as mine is almost always a ugly angry mess . I have great self awareness.. Its not 100% ... but I haven't been blindsided in a long time "knocking on all kinds of wood "

I think just waking up and doing a quick 2 minute self check is a very good indicator on how your feeling and is sleep in a okay zone etc