Fermenting/Primary question and conditioning question

First question is about fermentation... I read some people post stuff about leaving the beer in the primary for a month or two yet I read where other people leave it for 7 days... I brewed a stone ruination ipa and after 10 days, I checked it and it was at 1.019FG. I checked it 4 days later and it was still at 1.019. About 5 days later, I decided I would check it one last time and it was still at 1.019FG so I dry hopped it... Why should I wait longer if the hydrometer doesn't lie and it basically is letting me know that it is done fermenting??? How does it help to let it sit?

Second question is about carbination and conditioning. I was told that when you carbonate your beer and bottle it, you should let it sit for 2 weeks and check it... have a sample bottle. Then repeat at 3, 4, and 5 weeks. They said when you will know when it is done.... Then I have seen other posts where people say that they can see that the conditioning is done.. What do they see? What are they looking for? This is an IPA that I'm working with and I have been told that IPA's will lose their hoppiness over time along with aroma, so I should wait very long.

You are correct that fermentation is done when gravity readings remain the same. The yeast do need a couple of days to clean up byproducts. Larger beers will get better over time. For your second question, I'm not sure what people see. If they bottled in plastic then they could feel the bottles for carbonation but in terms of really knowing you have to open a glass bottle and try it.

Your question about fermentation can lead to some nastiness on here as there are two sides to all fences. But, for what you did, you are fine when you see gravity readings the same day after day. When brewing IPAs people typically want to get there beer in glass as soon as possible. The hops are so volatile that it is important to be tasting fresh while the hop flavors and aromas are at their peak. Bottle conditioning is typically a two week process and fermentation another week, two or more . If you dry hop you could be at least five weeks out before tasting.

My beers typically take 3 weeks or so to ferment out & settle clear or slightly misty before priming & bottling. 3 weeks at 70F or so is the norm,but can take 4 weeks for conditioning flavors & aromas to peek. 1 week fridge time gives any chill haze a chance to form & settle while getting plenty of co2 into solution.