Spare bedroom in my condo build in 2009 has a shower. It is almost never used, but I noticed there is almost no adjustment between hot and cold. You move the handle one way you get hot full on, a tad the other way much colder.

I assume I could just replace the cartridge, but it seems strange that it is acting this way, especially since it's never seen any real use.

Is this proper repair or something else wrong?

Thanks.