I don’t know what the building codes / rules are where you live, but where I live (in the US), there is supposed to be a smoke detector in every bedroom. Newer code also requires them to be hardwired so 1) no batteries to change and 2) if one goes off, they all go off.

I put kiddie z-wave enabled smoke/CO detectors throughout the house, including one in every bedroom. They are linked into a monitored alarm system (abode), but that is mainly for keeping track of things when we are not at the house, and I m going to eventually switch to home assistant.

Since the main ones are already wired in, you could probably add at least the dumb smoke and CO detectors to every room for extra peace of mind.

Independence Day. That shot of the White House being obliterated was amazing at the time.