Ugh I know the struggles! I ended up going with a ring guard and will see how the summer will affect the size of my fingers (swelling etc) I have really tiny fingers but in the summer they swell first and I dont have a/c. I got these from Amazon and they are the best: https://www.amazon.com/RinGuard-Ring-Size-Adjuster-Small/dp/B017N55540/ref=sr_1_2?ie=UTF8&qid=1489621788&sr=8-2&keywords=ring+guard
as someone whose fingers shrink and swell quite a bit due to temperature/weather: don't size it for your smaller size. if you do that, you'll never be able to wear it in warmer weather when your fingers are more swollen.
removable ring sizers are a life saver. these are my favorites; you get a pack of three in different lengths. the longer ones are great for the depths of winter when my rings would literally fly off my fingers. i took one and cut it into even shorter pieces, and those are good for those medium days when my rings aren't in danger of falling off but they spin a lot. here is a photo of the smallest one i've cut, which i'm wearing today because it's a bit chilly. they're all very comfortable to wear and easy to put on/take off as needed.