generally 100mah is 1 hr. thus 150 is generally 1hr+.
and thats not accurately cuz battery power drops over time and also u dun vape the whole hour do u lol.
so 150mah prolly last u like 3hrs on normal usage.
i've had my mini ecig lasting me almost half a day. or under 1hr of chain
vaping so it really depends on often u use it.
best to get above 650mah like some suggested. that way you should get thru half a day w/o recharging but have the habit of bringing spare batts. u dun wanna fall back to analog when battery runs out.
Easiest setup would be a ego 1000mah plus ce4+ aka vision stardust.
that way u get to explore ego threading accessories and 510 threading accessories w/o compromising battery power as well as vaping standard.
if u're into vaping and wants something more, sooner or later u'll upgrade from ego but ego is still the best hassle free setup thus far.