Changing the strings

I am wondering about when you should change the strings and how long the strings usually stay on the uke. Is there a set period of duration before you should change the strings or is there a noticible sound difference that you would hear? My strings have been played for six months as of now.
Thanks for any info!

I'm not sure if there is a set amount of time for when you should change your strings. It would all depend on how much you're playing, I guess. For me, I change mine whenever the low-g starts to break.

I change them whenever they show excessive wear from the frets. With wound strings, that means probably every two or three days. With plain nylon/fluorocarbon, I'm good for a few months. The sound doesn't get noticeably worse until they've been on there a long time and have been played a LOT.

I change my strings every 6 months or if they are showing excessive wear from playing it too much. I recently had to change my strings on my KoAlana concert ukulele after 4 weeks.

Lots of people have lots of different ideas about this, ranging from changing at a specific time, to not changing unless one breaks. Different string brands wear differently and may show different signs when they start to get fatigued, but here are the guidelines I use.

Bad Intonation (This is my most frequent reason for changing. It usually happens with my A string first, if I wait too long E follows, etc.)
Start Sounding Dull or "Dead"
Start Showing Wear or "Feeling Funny"
String Breaks

I've had strings last months, while other strings last mere days. String life (shortest to longest) in my experience seems to be wound metal, wound nylon, nylon, fluorocarbon, nylgut.

Thanks for the info!!