My lab uses the primers from IDT but since I arrived here I noticed that when the primers arrived they work perfectly but then I started to notice that the bands in the gel become faint and after a while there was not amplification at all. Then, I prepare new stocks of primers, but with the new stocks, there are not amplification at all or the bands are too faint. Then I add DMSO , and the pcr started working again but then after a while it stop working again, and so on. I have been dealing with this a lot of time, I have changed all the components of the pcr, but nothing. So, I really believe that something is wrong with the primers, so I would like to know if someone else has faced this kind of issues.