I started carrying my Mini^3 with me everywhere when I first got it, but lately I've started leaving it at home. Mainly for 2 reasons - one, my 'on the go' listening is now mainly through my iPhone with my SE530 IEMs; the extra bulk and high gain of the Mini^3 isn't really something I want to contend with. The 2nd reason is that the while the Mini^3 is a great little amp, it is just that - an amp.
One of the reasons to carry it with me are for those days when I know I'll be able to take advantage of a longer listening session with my Macbook Pro. Alas most of the time I've found that the native Macbook Pro output has some distortions and occasional flaws. Still I need the amp for those longer listening sessions which are usually with my Beyerdynamic DT770 Pro/250s.
Because of the occasional flaws in the Macbook Pro output and my source material, I found that I was better served by just using my SE530 IEMs for the majority of my listening. For the most part this doesn't require an external amp.
That will likely change again soon - my Headamp Pico is about to ship and I suspect it will see use with both my iPhone, Macbook Pro and the SE530s. The IEMs are likely to have better synergy with the low gain setting available on the Pico, compared to the fixed 5x gain of the Mini^3.
Of course I am anxiously awaiting the use of the USB DAC in the Pico as an alternate to the native Macbook Pro output. Based on comments and reviews from other Pico users, I will not be dissappointed.
Thankfully the Pico is such a small package that carrying it won't be an issue. Of bigger concern will be carrying the DT770s for use in high-gain mode. Who knows, I might tend to use my SE530 IEMs even more with the Pico in low-gain mode. Only time and experience will tell, but it's definitely something I'm prepared for and looking forward too.