Depends on how many skills you want to learn, total. The costs of brain decay for those learning more than 30+ skills, however, mean that if you don't take the time now, you'll be stuck taking the time later. It's best to learn Better Learning sooner than later, although not necessarily before getting the basic gathering skills down.
I have 44 skills currently. I only have BL 3. It will take me over 7 DAYS to learn Mining IV. So take that into consideration. I would get the BL skills down first.
I just finished with BL5 and took screenshots of my skill times : Before
and After
I know sometimes its easier to see examples then try and comprehend all the math involved LOL
One thing to consider: "the majority" often don't take opportunity cost into account.
For my playstyle and the limited number of long-time skills on the tree, BL5 doesn't make sense. Consider what else could you learn instead of BL5 for that entire week, and how the benefit of using those skills compares to shorter training times down the road with BL5.
To anyone arguing against BL5, are you planning on only playing this game for a couple weeks? If not, and you are not in a race to learn other stuff....who cares that it takes like 5 days. When it's done you'll be flying through all those little ones.
another factor--I believe the devs have mentioned from time to time that there will be more skills to learn as the game develops. an example is the recent introduction of Eyeballery and Snapshotting. I am guessing that the Giants are imagining greater skills even as we speak.
soooo, it will always be to your advantage to have all the BL you can ...er ...learn.
Learning BL4 dragged down some of my long-learning skill timers by about a whole day. (BL5 and Mining 4.) They went from 7 days to 6 days. Back up to 8 days now though.
Planning to tackle BL5 next. Just need to hoard up enough stuffs to donate...
I did the math recently when I had 40-some skills. And without being all boring-numbers-y, learning BLV (which I'm still doing, BL4+5 together totaled about 12 days for me) will shorten the time to learn the entire tree.
Eventually every skill you learn above 37 skills adds time to all skills. For some of the longer ones, you'll rapidly be adding days to their total costs.
One way to balance the opportunity cost is to learn short skills you want immediately while online, and switching back to BL5 (or other long but important skill) overnight. I agree with Kraftmann that there's opportunity cost associated with trying for a strict shortest-learning-time path through the skills, but Better Learning has an enormous impact over the long haul.