Drilling the Limit (DTL ™) is a powerful initiative to drill wells at minimum time and cost using best-in-class technology. Pre-requisite to drilling at the technical limit, however, is that the borehole is "perfect", i.e. the borehole is stable enough to eliminate downtime from stuck pipe and lost circulation incidents, the annular clearances are sufficiently free from cuttings to minimize wiper trips etc. This requirement is nontrivial when drilling challenging wells, e.g. wells drilled at high deviation and extended reach in reactive formations, wells in tectonically active areas, wells in deepwater environments with very small drilling margins etc. Achieving the "perfect" borehole for such wells is facilitated by including an integrated borehole stability (IBS) study in the well planning phase and by implementing its guidelines during well execution. A review of the IBS process is presented in this paper with actual examples of IBS results that were used to enable DTL ™ and minimize trouble costs on challenging wells.