I recently heard that breaking in middle of the prayer is a bad thing, but I still don't know how bad it is it, whether it is a serious sin or just a hated action, or whether there are anything from what our Prophet (pbuh) said to support it.
Many times I lose concentration in middle of the prayer, so what I do is say the salam when I completely lose concentration of what I am saying or doing and redo the salat from the beginning. Is this acceptable?