The spacing rules are for combustibles. Don't operate any appliance capable of supporting a grease fire, and that's all smokers, while up against wood siding. Stucco or brick not a problem. Now if there's a one-story roof rafter overhang <10' above you, that's also combustible and is an excellent way for fire to quickly enter dusty attics and cause extensive damage. Avoid that as well. Most smokers with 6' cords are safe to operate within 6' of most interior walls. If not, get a 12AWG 3-wire extension cord.
These are all rules for that 0.01% probability of a grease fire. But the rule about not letting smoke get in your neighbor's window applies all the time. Lighting a wood match can give you a some idea which way the wind is blowing. You may not always be able to smoke in an apartment complex. Regardless the rules, you can probably run certain smokers 1000X if you know where your smoke is going because you'll get no complaints. But get one complaint, and you'll probably have 100 people quoting the rule against smokers and BBQ's to you.
I like the idea of rolling a "stack" and directing/funneling your smoke into it and thereby out above the roofline, but that usually involves mounting something to a roof overhang and not all apartments dwellers can get by doing that. I have a conventional 2-story home in an old-fashioned neighborhood. My neighbors don't complain about smoke but my wife does. I'm considering a 16-foot vent pipe on a pulley system that's only erected into place on smoking days. But to tell the truth, I'll miss the smoke smell myself on smoke days. However the meat should then taste better...I really think we saturate our olfactory nerves on smoke day. And that's why leftovers seem to taste so much smokier to the cook...we've recovered by then a bit!