Zillions of moggies go outside and live long lives. Worry less unless you live in a highly urban area like the city, where IMHO you might not want the cat to go out.
Cats are on the whole fairly smart and savvy about cars etc.
Or at least the ones that survive are..
Having said that - there are other dangers - my Manx got poisoned from a bad rat (the rat had eatn poison and she got it from the rat), and had sizures and cost me 2,200 dollars of vet bills over Xmas. She seems fine now, BTW.
My other Cat Diablo (the best cat I have ever or will ever own) got hit by a car (grazed actually) and miracle of miracles survived with minimal damage at age 11 years. He is now 16 going on 17 years. Soooo....
Diablo would never have been happy indoors - at one point when he was young, we had to make him indoors in the city. My solution and his was to leash walk every single night for poops and tree scratching...(which you know he took to remarkablely well...) When I got to the suburbs I lived on a park/lake and he had lots of safe areas to roam, so out he went.
He got in many many fights (he's a scrapper) and chased dogs.
His leash habits made him popular at the vets, since he never went
in a carrier - only leashed. He would wait paitently on the vet's counter
till it was his turn to be seen. The vet's staff always were amazed
at Diablo, LOL!
He now has arthritis from the wounds, plus the car accident. But he still goes out and isn't happy if he doesn't get to stretch and claw and poop outside... even as a geriatric guy!!
I have another cat Shebs entirely content to stay in or sit on the porch and nibble grass from a basket...Has been like that her entire life...She's 17 and in worse shape than Diablo with hematomas in her ears, hyperthyroidism, and arthritis up the wazoo. But, she never went outdoors, except to laze in the fenced in back yard...
I had a pet door for them, so they could come and go as they pleased.
My cats have always been Indoor/outdoor despite the dangers. I feel they are happier and more "natural" that way.
For the record, I've never had poop elimnination problems, clawing of furniture or spraying. Ever. I attribute it to the fact they go outside...
Of course, I also know I could lose my cat to a car or something one day.
I worry about it alot, but let them out despite that because they need
the exercise and I think it is better for them mentally ...
When I'm away its a different story and they stay inside. They always
hate it and are desperate to get out when I get home...
Indoors makes sense depending on your location, and the flightyness of the cat. Some cats simply are dumb about the dangers. No ever taught them.
Me, I tried to teach my cats, but Diablo seemed already to know about them, LOL...
Outdoors makes sense if you've a cat that has a urge that's too strong
to tame or re-channel...