I'm not sure exactly how many Indians cards I have, but my last estimate was somewhere around 10,000+..
It's really hard to get organized, especially since with that many cards, binders are not practical. I do have a lot of cards separated by year/set, but it has been a while since I've done that, so I have a few thousand that need to be put into order.
As for how I keep track of everything, I just use three separate Word Documents (one for 2000's, 90's and pre-'90)... It's not a terrible way of keeping track of stuff, but an Excel spreadsheet would probably work a lot better. The total of the three Word files is about 280 pages long, so if I were to change now, it would take A LOT of work, haha!
Best of luck!