They are pretty stable when stored away from heat, light, and moisture... I think the rule of thumb is tryptamines are subject to degrading a little more quickly but in any case I would say if you don't plan to use them up within 3 months, store them in an airtight mason jar in the freezer with dessicant packs and/or dry rice. I have chems that are coming up on a year old and they have not lost potency since they have been stored that way.
Most of the 2C-'s are very stable at room temp. Keep them out of the light to be ultra safe [you prolly do anyway], but they should be fine either way indefinitely. The tryptamines as a class tend to be a little less stable. DPT HCl should be fine too, but not real sure about that. Moisture and light are the real threats. Heat just helps speed up the reactions that degrade these chemicals. 4-AcO-DMT fumarate (yes the fabled "stable" salt version) apparently darkens (evidence of degradation) after a few months, even in the freezer. I haven't seen that but that's what dem sciencey paperz tells me. I had some 4-AcO-MiPT dissolved in water that turned it darker but there was no perceptible loss in potency. Mirroring the other documented 4-AcO- subd tryptamines reports of degradation without potency loss.
Dpt kept at room temperature in the dark did not lose any potency for me for ~3 months. I don't see why you would subject any of these chemicals to light but I don't think extreme measures need to be taken to keep them at freezing temperatures, room temp should be fine.
