Time To Change Strings

I'm still quite the beginner, but think that I have finally determined when it's time to change strings. I got my tenor for Christmas and have played it a lot since. I tuned it up the other night and it did not tune as easily as before. It seemed to have a higher pitch, but also had a "choked" sound, not the nice ring it normally has. I haven't changed them yet, but am sure that is the problem. BTW it is a gloss, mahogany Mainland. Any opinions?

Sounds like time to change them to me.

I change my strings when the intonation starts getting a bit off. Usually my A string is the first to go.

Time to change strings. I just got my KoAlana Concert Ukulele and I had to change my strings already. My KoAlana from KoAloha is only 4 weeks old. I try and change my strings every 6 months or earlier if the intonation starts getting a bit off. SailQwest, my A string is also the first to go too.