Does anyone know if it advisable to buy out investors.
Can you increase profits without them? Can you get do it at a price that provided a good return? What are the financial returns of the buyout? It is like any other financial decision - if your return is better after the buyout - then yes - if not, no.
when you are at a point where the business is self sustainable and you don't require additional capital, it may be smart to buy out investors if 1) they are not carrying their weight and 2) you know the business has upside. otherwise, why would you want to buy them out to begin with?
What was the reason you took in the investors to begin with. If it was strictly to get the funding that you needed for your business, and you have reached that goal and can now afford to buy them out then go for it. If however the reason you took them on was to get funding, and eventually if the business takes off to further use their funding to acquire more business opportunities, then their work is not done yet.