Potency will not be lost through the clone process, actually. I believe as a person grows a specific strain, and learns it's quirks, and you bet they "all" have their own little quirks. You become quite expert at your strains, and in fact the quallity will go up just on that merrit alone, Also If you work the strain long enough, and carefull enough, you will find fem selfed seeds, This opens the door to psudos that could end up better than the original. Ya just never know so go ahead and clone, and get good at it. There are a variety of ways of making clones of your mother plants. Check out my journal on Air cloning these roots are grown right on the mother plant, Before ever cuting the clone loose the whole process is done right on the donner. Also if you are procuring clones, take your 420 scope with you, if there is question of pests, loop the plant and media, check for pests you are going to see them if they are present. as for disease not alot of plant disease out there that is comunicable from plant to plant. There are a few but in controlled grows its very unprobable. unlike infestation.