It depends. a dipole in your apartment/condo is just fine at QRP power levels. if you plan on transmitting at 1000 watts, well things will get really exciting for you.
I have a 10 Meter dipole ran at the peak of my house in the attic, works great for the directions I want to talk.
Everything else I use a current Loop antenna that is smaller and easily turned. or if I am portable when camping I use a BuddiPole/BuddiStick setup. Those also work indoors, but again, if you are at 100 watts or higher, RF feedback and RF exposure to yourself get's really wacky. I have seen guys fry their own gear when running 500 watts on an antenna that was only 30 feet away from themselves due to induction.
A lot of hams claim that more power is good. It's not. 5 Watts QRP you can easily talk around the world on. and it's a lot easier to do in an apartment/condo setting.
Add PSK31 digital mode into the mix and suddenly you are talking to people barely above the noise floor 1500 miles away.