I don't know where the flies in my apartment are coming from recently (no exposed food/garbage or opened windows, etc), but I know they're there. It's not a huge infestation, but it is an annoyance. Regular-sized flies, not fruit flies.
It seems there are two main alternatives for killing flies, outside of using a swatter (which I tried, with an electric swatter, but the ones in my apartment are too restless and quick) and poison spray (toxic, gets over stuff, needs cleanup, etc). Those two alternatives are scented traps and zapping lights.
The scented traps seem recommended for outdoors due to the strong smell, so I'm wondering about the issue of the smell being in my apartment, including with regards to how hospitable my place would be while the trap is there, whether the smell lingers after the trap is removed (and if so, whether something like an ozone generator would take care of that), and crucially, whether the smell would be strong enough to attract flies from outdoors through the tiny pathways connecting the outdoors to my apartment, which is obviously unwanted.
So, normally I'd select zapping lights. However, I read that unattended zapping lights are a potential fire hazard, and in my case, they would be almost entirely unattended at the moment. I've been staying at my girlfriend's, awaiting cleanup of the apartment opposite mine that suffered a fire a month ago (that's why I bought an ozone generator, but it's not enough to stop continued transfer of the smoke smell from the opposite apartment); I now only visit my apartment periodically, generally once every few days or less, for up to several hours at a time, not staying overnight.
Regarding another alternative, fly paper, I read that it's unreliable, especially for bigger flies. But I'd like to be proven wrong.
So I welcome advice, preferably based on experience. And if I didn't mention a trap style that you think would be more suitable for my situation, please note. Thanks in advance.