2021 Taycan 4S
In the Taycan's Brochure (On Page 51 under "Important Information") Porsche recommends that "the maximum charge status of the high-voltage battery should be set to approx. 80%" if you plan on charging the Taycan on a daily basis.
Their reasoning in the brochure seems to be "For physical and chemical reasons, the charging speed decreases as the battery approaches its full capacity. Therefore, it usually makes sense to use fast DC charging to charge the battery up to 80% or up to the required range."
I've seen this suggested for Teslas and other EVs, I assume this is the sweet spot for battery longevity?
Good to know. I don't charge my 4S every day as I live in a high rise apartment. Usually charge mine once a week and always go to 100%.