AR, time, tunnel length and geology using QTBM is the title of this chapter and summarizes the intention. In detail the case records, including world records, all point to the importance of accepting a time-dependent and tunnel length-dependent advance rate (AR) which of course gives different final results compared to net penetration rate (PR) prognoses. A mean PR of 2 m/h and a final AR of 0.5 m/h after roughly 2 years may be experienced in hard and partly faulted rock also in the case of double-shield TBM. With open-gripper TBM the decline is usually steeper. In the QTBM concept PR is only a starting point, and after a learning curve, numerous case records show that AR declines from week to month to year due to geological challenges such as very hard rock, and/or due to serious fault zones and perhaps problems with water, the latter two requiring pre-injection with associated delays, the former requiring excessive cutter changes. The standard AR = PR × U equation is recast to a more realistic U = Tm (total hours, raised to the power m, the negative deceleration gradient). The negative gradient m becomes more negative in faulted rock (low Q) and also larger in extremely hard massive rock (high Q). TBM performance is also compared with drill-and-blast and suggests the need for ideally jointed conditions for a TBM to be consistently faster than D and B when a tunnel is for instance longer than 10km, and perhaps already taking 2 years or more.