On a more serious note...
It all depends on what you want to listen to. If all you are after is your local community's public safety frequencies, and they all use decent repeater systems, you would be just fine with the stock whip on the radio. (I live so close to my city's PD/FD repeaters I can listen with NO antenna.)
If you want to listen to more distant or weak signals, you may need something better. But size isn't the only - for that matter, at VHF and up frequencies, even the most important factor. More significant in that range is height above ground. A simple discone can receive better than a high-gain antenna, if it's sufficiently higher than the high-gain one.
The simple/cheap solution would be to try the indoor antenna first, then if you don't hear what you want to try something outside.