I've been looking for info on long term data retention in flash memory for a while. Exact details on flash lifetime are surprisingly scarce. This paper provides

I've been looking for info on long term data retention in flash memory for a while. Exact details on flash lifetime are surprisingly scarce. This paper provides a nice overview of the electronics of a MLC NAND flash cell, and the reasons behind them degrading over time. The authors propose two ways of increasing the resilience of MLC cells.