How long do seeds last?

Hi, I bought some schwag once about 3 or 4 months ago that had a bunch of seeds in it. I kept the seeds and there were about 15 of them. I tried planting some of them in some pots that I kept on my porch that are usually used for tomato plants and none of them worked. I tried that about two months ago. Now I still have the seeds and there are about 12 of them left. I now realize that the reason they didn't work the first time may have been because they were not germinated in any way. I have read stylez1877's thread about germinating seeds and I plan to use his methods to germinate the seeds I have. Now I am wondering if these seeds are still good 3 to 4 months after I got them. I've just kept them in a ziploc baggie that I usually try to squeeze a lot of air out of. I'm also planning on planting them in cups the same way that stylez1877 did in his thread and then possibly attempt to plant them in some woods nearby my house or just plant them there to begin with, thoughts? You don't really have to answere that last question as I believe I may be able to find it in another thread, but feel free to answere it if you wish. I apologize for any spelling, gramatical errors, or the wall of text in my post. I am currently taking a tolerance break and haven't smoked for six days and I am currently drunk, which is something I usually only do on tolerance breaks. I tried my best to make this a coherent post and I will edit this in the morning of any gramatical errors and break this down into paragraphs in the morning, but I am finding it a little difficult to do so at the moment. I apologize for any difficulties you may have in understanding my post, but will fix them as soon as I am sober.