Best way to quick level retainer? What do you do?

[Snugglebutt]

I do 18 hour ventures to level then switch to 1h ventures when level capped. I do this for couple reasons, first being I can't be bothered to constantly farm fates to buy more venture tokens so spending 2 tokens each time send one out every 18 hours is preferred by me. Especially since I have 6 more retainers (out of 8 in total and 2 already capped) in the process of leveling.

So much better to spend around 12 tokens for leveling them every 18 hours rather than 12 tokens every single hour. It would require wasting 10-20 minutes every hour farming fates in order to keep up spending so many so often which I am not willing to do. Secondly 18 hour ventures also give unique rewards which cannot get from 1 hour ventures so I try to get those while leveling such as the unique pets etc, switching to 1 hour when leveled to cap and just need the retainers to farm specific materials or generic income generation.