Britney Spears -- Lifetime Conservatorship

Britney Spears has been under a remarkably successful conservatorship for 7 1/2 years, and sources familiar with the situation tell us it could last a lifetime.

We're told there are no plans to end the conservatorship, even in the long term, and no one involved is complaining. As TMZ and every other media outlet reported, Britney was so bad off at the end of 2007 her family was in fear she would die.

After she was taken to the hospital on a psych hold, her dad, Jamie Spears, went to court and a conservatorship was established in January 2008. There are actually 2 conservatorships ... one for the person, and one for finances.

Fact is ... the conservatorships have worked remarkably well. Britney -- who at her worst was on the verge of losing permanent custody of her kids -- is now by any standard a great parent. Jamie and Britney's doctors have stabilized her to the point she can successfully work and maintain a personal life.

As for the financial conservatorship, it has been a huge success. Last year alone the conservatorship raked in $14 million, and that's only a portion of Britney's financial machine. As one source said, before the conservatorship her finances were an absolute mess, and the ship has been fully righted.

We're told Britney -- who has a team of lawyers and doctors, along with Jamie, managing the conservatorship -- has "substantial day-to-day freedom" to make her own decisions.

Short story ... if the conservatorship were to end, there would be significant risk she could backslide. The plan is to continue the conservatorship indefinitely ... because it works.