Hi, all -
There are several kinds of equanimity and several ways to develop equanimity.
[MN 137 Salayatana-vibhanga Sutta:] "And what are the six kinds of renunciation equanimity? The equanimity that arises when â" experiencing the inconstancy of those very forms, their change, fading, & cessation â" one sees with right discernment as it actually is that all forms, past or present, are inconstant, stressful, subject to change: This equanimity goes beyond form, which is why it is called renunciation equanimity. (Similarly with sounds, smells, tastes, tactile sensations, & ideas.)
[SN 36.31 Niramisa Sutta:] "Now, O monks, what is worldly equanimity? There are these five cords of sensual desire: forms cognizable by the eye... tangibles cognizable by the body that are wished for and desired, agreeable and endearing, associated with sense desire and alluring. It is the equanimity that arises with regard to these five cords of sense desire which is called 'worldly equanimity.'
"Now, what is unworldy equanimity? With the abandoning of pleasure and pain, and with the previous disappearance of gladness and sadness, a monk enters upon and abides in the fourth meditative absorption, which has neither pain-nor-pleasure and has purity of mindfulness due to equanimity. This is called 'unworldly equanimity.'
"And what is the still greater unworldly equanimity? When a taint-free monk looks upon his mind that is freed of greed, freed of hatred and freed of delusion, then there arises equanimity. This is called a 'still greater unworldly equanimity.'