need a clarification on conversion tracking

window.document.getElementById(‘post-3845’).parentNode.className += ‘ adhesive_post’;can you track both leads and sales with conversion tracking or is it advisable to just track one
my sequence
squeeze page—-> thank you page —-> sales letter —-> order page
i placed a lead tracking code on the thank you page
i also placed a code on the order page as well
is this ok or should i do one or the other

Original post by crischico