I have made heaps of tomato sauce and tomato relish over the years (non -TM and TM)I found that I had no problem with tomato sauce and relish lasting 6 to 12 months the non - TM way (but that is cooked for quiet a few hours and cooking up 9 kg of tomatoes)With the TM recipe I think you would have no problem with it lasting 3 months. But as you only cool up a kg of tomatoes at a time you only getting a couple of bottles which you should be able to use up in less than 3 months. I use the relish in lots of recipes as well as on it's own so we go through quiet a bit.