How long for each active recall?

Simple question

I sometimes even think 30-60s or even more before I remember or flip the card but that feels pretty time consuming and draining on the willpower if you have plenty of cards to go.

How much thinking time would you consider most effective to allow yourself before you flip the card and with what reasoning?

Thank you

This depends on the materials you are learning, how your cards are formulated and whether you are adhering to the minimum information principle.

I sometimes spend minutes on equation-heavy cards while failing them again and again. This illustrates the need to reformulate those cards to ideally separate them into multiple simpler cards.
Another type of cards I spend some time on are language learning cards where I test my ability to use a word by writing a sentence.

Anki stats tell me I spend about 8 seconds to answer a card on average for my whole collection.
Michael Nielsen, in his great article about memory, says it also takes him about 8 seconds to answer a card on average.
I think maybe aiming for answer times under 10 seconds is reasonable for most types of cards.