"Kimchi is the best ingredient that can be used as main dish or ingredient in any type of food", is the statement you can find everywhere in internet. But how good can this one ingredient or dish can be is the real question? 
Anyone can write about kimchi in a very exaggerating way but in the end as a consumer we need to know whether it is worth the penny or not. It's not about bein very calculative but it is how we should always think.
Really how long can kimchi stay and can it go bad even though it is fermented are the questions now.
Let me answer one by one
1. How long can kimchi stay fresh
- The answer can be different for 2 different situations
a) In refrigerator at the temperature of below 4 Celsius Kimchi can stay fresh for about 3 to 6 month.
Precaution: Longer period than 6 months may lead to more sourer taste.
-This factor has a back story, Kimchi was invented in Korea for winter season. As in winter the temperature is very low, Kimchi was helpful since it can stay fresh throughout winter season.
b) In room temperature Kimchi can stay fresh for 1 week only because in room temperature the bacteria are active. The bacteria in the wind and the temperature accelerate the spoilage.
Retrieved from https://www.healthline.com/nutrition/does-kimchi-go-bad