Chas

The best advice is buy sample sizes, on sale, if possible. Lots of good juice vendors. Most vendors list their top sellers.

I was about a pack and half a day and started with 18. Had no problems at 18 and 16. Tried 24 and it gave me a headache.

I have four Riva's (750) and ego's 650, 900, 1000. The bigger batteries last longer. The button on the riva's are different and depress easily. You have to be careful. I perfer the 750's and 650's because they're small. I just carry extra batt's.

Charging on the wall charger (outlet) is faster than though a PC.