That is a resourceful post. As you stated, there is no one single approach to tuning a proc. It is purely a case by case issue, so a variety of testings have to be made after baseline numbers have been taken, and thereafter, examining and comparing new readings of various performance indicators. with each modification. The fact is that you have to start from somewhere, and eliminate those indicators that do not improve with changes until eventually, the real cause(s) of the performance is identified and then tweaked to achieve improvement. As stated, it could be problems with indexes, memory & I/O, temp tables, network, how the T_SQL itself had been written, contention of server resources etc... I think one of the principal problems is identifying the real cause of the issue, and that has to do with using the right tools and understanding the tools in use.