>>1230757well homeless people generally quite poor. that means shit food, malnutrition in some nutrients. No money for doctors or even just over the counter medicine. that means diseases burden the body longer or permanently. lack of hygiene makes this and parasites more likely. Hard condition leave the body under constant attack. Sunburns in summer, sore in winter, trench foot in spring.
over time normal stuff can lapse too. like after years vaccinations run out, dental work need to be done.
Some mental problems are contagious like alcohol or drug related, or for example fear/ paranoja from long exposure in hostile, violent, lawless, lonely and distrustful environments.
so yeah unless you are trustafarian or champagne hippy this shit sucks over long term for most people. sure some can make it work, but that's a minority.