Legendary Transfer v Trade

It's likely that we'll get raid days for the beasts soon. I think the raid days were wildly successful, very fun for players, and generated a lot of passes sold for Niantic. Sure, the first set was a reward for completing Professor Willow's global challenge; l suspect they will find another thing to reward us for with raid days for the beasts, or they might do Lugia/Ho-Oh first. But I don't see that style of event going away.

So for Raikou, you can probably try to get a good one at it's raid day, no idea when that will happen, but there's no urgency, as there's no raid coming up where electric is king.

Try to view the legendary releases as a series of things, the current raid bosses, the Field Research Breakthroughs, and the raid day stuff. Each one is moving through the list of legendaries in its own order and at its own pace.

Mew and Celebi will come to you in time, just keep working on the quests. Regi's are dex fillers, Latios and Latias have niche uses.

Bottom line, though, you've been active here long enough that you should have a good idea what's good and what's garbage.

The other question you need to ask is, "Is it worth 40,000 dust just to get 6 candies for a legendary?" There are good reasons to trade a legendary, but it's a steep cost, and the candy gained is a perk, not the driver for the trade.

Are you planning to sit on all of them until the next trade bonus event? Keeping in mind that there's no precedence so we don't know for sure if they're even planning on repeating it and if they do, it's likely several months away still since the last one was a month ago.

The candy bonus applies to candy you get, so it's mostly up to what you value and secondarily dependent on if anyone wants to trade for that legendary. The most desirable ones are obviously Mewtwo and the weather trio. Raikou, Moltres, Zapdos and Entei are ok too. But the only one who can decide which are worth saving is you.

One thing I want to bring out is the possibility of the Halloween event having an unlimited double candy bonus. It should be in 3-4 weeks which might mean it's better to put off this decision until then. But if any of the legendaries are ones that you never intend to power up, you should trash immediately since the potential extra candy doesn't have value for you.

I'd say sit on them until we see what Halloween Event has in store for us. Each Year Niantic did a Double Candy event so it might just apply to Trading to. You could get 6 legendary candy for trading over 100k distance.

Thoughts:

You can't trade Mew or Celebi so that's irrelevant.

You can only do one Legendary (or other special trade a day), so that's only 10-12 (if I remember the length correctly) boosted trades.

I will be transferring my extra Articuno and Zapdos, while potentially prioritizing trading my Moltres to power up both my Sky Attack and fire options.

I'll probably transfer my FB or Psychic Mewtwo as well as any Flamethrower (haven't been raiding at all since he rotated in).

I'll also probably trade my weakest Kyogre and Rayquaza of my three each as well as a Latios or two and any chump Raikou.

I'll also transfer my miscellaneous Regis, Lugia, and Latias.

All in all, I'll probably pick up 30 free spaces in my box, maybe 40 depending on what my trades roll to. (Like for like would net up to 8 candy with trade and transfer.)