Thanks for your question. The length of time in each step depends on the nature of what you're selling and who you're selling it to. However, the Apply step is all about demonstrating your solution and the Convince step is providing third-party corroboration for your claims. You should only move to the Convince Step AFTER you've fully applied what you're offering to what your prospect is looking for.
P.S. Thanks for reading Perfect Phrases for the Sales Call.
"Selling is like shaving. If you don't do it everyday, you're a bum!"