The difference between most of the popper sizes is a factor of 3, i.e. 10ml versus 30ml. The 1oz size is roughly the same as a 30 ml. There are also several 15ml sizes as well which are half of the 30ml.
Most people buy 10ml bottles and there are more brand choices in the 10ml size, although some brands, i.e. Toro or Texas, are only available in the 30ml size.
The longer a bottle is open the more it will degrade although I have had bottles open for months that still pack the original punch.
Keeping the bottle closed tightly and in a cool place, or better yet in a refrigerator/freezer when not in use will extend the life. If you keep it refrigerated or frozen you need to let it come to room temperature before attempting to use it.
Some people buy a 10ml bottle and a 30ml bottle, keep the 30ml in the freezer and use it to refresh the smaller bottle as needed.
Another way to extend the life of your popper purchase is to use cotton rolls, like are used at the dentist, to soak up some of the poppers and use the cotton roll tucked in a plastic vial while leaving the bottle itself tightly sealed in a cool/cold place.
If you store the plastic vial with the popper soaked cotton in a cool/cold place, you can continue to use it until it runs low and then you just re-soak the cotton. You never have to worry about spills this way. To soak the cotton, hold one end with tweezers, insert other end into popper bottle and allow the liquid to soak up into the cotton. Quickly transfer to the plastic vial and seal both the vial and the popper bottle.
As a bonus, email me when you place your next order and ask for a vial and cotton and I will gift you one for having read this post!
NEVER store your poppers, regardless of size, in a hot place, such as a sealed car in the summer. Heat will destroy your poppers quickly.
Ultimately, the choice between a 10ml, 15ml, 30ml, or 1 ounce size is a matter of preference and how you use poppers. If you use poppers frequently you will be happier with a 30ml where more occasional users will find the 10ml to be a better choice. Frequent users often also choose to experiment with multiple 10ml bottles to find what works best for them.
To speak to your earlier question about differences, personally, I am all about Mutiny and Jungle Juice MAX at the moment. Both are based on isobutyl nitrite although the concentration is higher in the Jungle Juice MAX, whereas my previous go to choice was Jungle Juice Platinum which is based on alkyl nitrite which has a more subtle effect.
My best advice is to experiment widely to find what works best for you in terms of brand and size. We offer over 50 brands, including spray poppers, more brands than any of our competitors so we are a one stop shop for the brands you know you love plus those you just haven’t discovered yet!