I'm thinking about purchasing 2007 dodge charger
for 4300 but it has 236k miles...should I worry bout
how long it would last before I have problem?
That is high mileage. That is averaging 26,000 miles/year. IMO, I would be cautious of a vehicle with that many miles on it. Acquire service records if you can or a carfax. Get as much info as you can on it.
I would worry. Probably needs suspension components and other items that are just plain worn out.
It is likely worn out. Move on to another vehicle.