Updating a customer-related SESSION variable on pageload with an observer

When I update a custom field in the customer record, I want that to take effect on the next page load.

Initially I am using the notifier-observer in function zen_is_logged_in to get the custom field, as it is only used when the customer is logged in, but I see that function gets called multiple times on a page load so it's wasteful.

Suggestions for a better notifier/way to do this, that gets called once?

On the store front there is the 'NOTIFY_FOOTER_END' notifier in the respective includes/templates/YOUR_TEMPLATE/common/tpl_main_page.php

$zco_notifier->notify('NOTIFY_FOOTER_END', $current_page);

That is expected to be loaded once per page load, though also depends on the page actually loading to that point (e.g. a page error before that point will prevent execution).

Alternatively some file that gets loaded on each page load... There are plenty of places to tuck that away.

That worked for me, thanks.