I quit each one in stages and via multiple attempts. I quit smoking ciggies 12yrs ago after many attempts. The main deterrent was the price, ciggies are $38 a pack of 20 where I live which is financial madness. I went from every day, to just weekends, to just special occasions to just not at all....but i always maintained my daily spliff habit. So my addiction to nicotine and the baccy was still in full force. For me the paranoia when I got high was too much to handle in the end. My coughing got worse and worse, when i got stoned I would feel so disgusted with myself for smoking tobacco...I couldn't enjoy sessions of weed anymore.
So 7yrs ago I got my first portable vape an arizer air. It helped, but it never really cut the mustard. So I switched to just smoking weed flower via joints and bongs, it took about 10 weeks to transition, but switching to just straight flower really changed my relationship with cannabis. The high was so very different to spliffs, it took awhile to enjoy the flavor and taste the same, also the way I smoked a joint was different to a spliff. With a joint I learned to puff and bring a little extra air in with the inhale to cool the smoke so it didn't burn the hell out of my throat. I also learned to take smaller inhales at first. After time my flavor pallet to weed opened up and I could taste so much more...i tried spliffs and they would make me gag.
But after nearly 7yrs of straight smoking flower via joints and bongs....every time I smoked I would savagely cough my lungs out...this became happening all the time, even with joints. Again my high paranoia kicked in....And I started to worry about my health when I got high, which took the enjoyment out of getting blazed. So 2 months ago I did a bunch of research into the best vaping option. I ending up going with the S&B Volcano Hybrid, yes this thing is the high end and expensive....but god dam they bloody good. I have had portable and desktops in the past and they never got me as high as bongs or joints and they seemed to use more weed. But the volcano is the opposite, I seem to get even more blazed/stoned than before and I use less weed. They vapor bag option makes them kind of semi portable, will inflate a bag and smoke it while making dinner in the kitchen. Its the primary method I use now. My lungs feel much better just after 2 months, I still cough but about 70% less and not the harsh deep lung eye watering cough from a bong load.
Doing it in steps and not trying not to give up everything all at once, worked best for me. Good luck bro!