Originally Posted by merlinextraligh

Reason being is that the major difference between DA and Ultegra cassettes is that DA uses Ti in the larger cogs.

Personally I haven't noticed DA cassettes needing to be replaced because the Ti cogs wore out before the smaller steel cogs. (which might depend on how much you use the bigger cogs) But a DA cassette is certainly not more durable than Ultegra, and probably a little less durable.