Toddlers - do you level them to level 3 or level 5 before aging them up?

Yep. Unless it's the odd one off where I need them to not be their best (or I'm testing something). Otherwise, I strive for success.

I usually play on long, so it's usually level 5. Then I take advantage of collecting points for whims and pick away at character values.

I play with normal aging, so up to level 3 is usually about as high as I can get. I've only been able to get all the skills up to level 5 two or three times with very good circumstances.

I also play with aging off so they get to skill level 5 before they are aged up. Now that we have milestones I also try to get all of those I can before aging up also.

Level 5.

Used to be level 3 but now that all the ages are longer think my todds will easily reach 5.

I so give my toddlers the highest toddler skills & I also give them some traits thanks to the cheat codes. (That's through Vanilla play) :p

On normal aging with my playstyle, most toddlers get to 3 on everything, and only a very few get to 5.
Which I like. I like having only a few be gifted children who learn skills really easily. Similarly, I often don't manage to complete a child aspiration, and that's OK too because I don't want to have only gifted teens/adults.

It depends on the toddler. I typically have the first born max their skills because I have less sims to worry about. Usually by kid 3, I just cheat their skills or let them do their own thing. Same thing with child skills as well, even though no one asked. :)

At least three, but lately I just go for level 5. I find that normal lifespan is juuust enough time to get them to max all the skills if I micromanage them, and I've gotten pretty good at it.

I mostly go to 5 to earn the reward trait. Unfortunately that is not working anymore but I add the trait with cheats if my toddlers meet the requirements.