[ryno1]

I'm looking at Brewing my first shower in a few months. After all the fermentation is done I'm looking at adding fruit. How long can the fruit be in there?

[kramerog]

I put fruit in my keg and left it until the keg kicked about 6 months later.  The keg was generally in the fridge at 45F but spent considerable time outside the fridge at temps of 50-60 F.

I think the biggest risk to adding fruit to a sour is mold, which can be prevented by keeping air out of the vessel.

[dannyjed]

I leave the fruit in for about 2 months. Adding fruit will kick up fermentation again which will fill the head space with CO2.

[reverseapachemaster]

Congratulations on your first shower. It will be a life changing experience for you. 

Generally a couple months is all you need for fruit. Some fruit benefits from a longer extraction period and a few with less but the vast majority are good at two months.

[brewinhard]

Keep in mind, if you are adding fruit to a sour beer then, you will definitely want to wait for the majority of the brett and bacteria (lacto/pedio) to already have a good foothold in the beer. This way, their populations will be responsible for slowly fermenting the additional fruit sugars and not saccharomyces which will not spit out as interesting fermentation characteristics as the brett and bacteria can.
The brett and bacteria will take longer to break down the fruit, hence many of the suggestions to leave the fruit to ferment for a couple months or so. IIRC, some commercial sour producers may actually leave the fruit for up to 6 mos to be sure it is stable prior to packaging.