I am having a problem with my WooCommerce install where order update emails (which I think are scheduled using WP Cron??) are fired multiple times - some times as many as 7 or 8.
Would it be WPCron causing this issue? Would increasing the cron lock time interval fix this issue?
Also, if I have around 12k visits to my site each month, will WP Cron be having a considerably negative effect on site performance? In other words, will it be noticably faster and use noticably less resources if changing to manual cron jobs?
Lastly, if you do think manual cron jobs are better, what time interval would you recommend we set for triggering manual cron jobs - about every 15 minutes? Or more/less frequently?