How do you deal with a valuable recurring client who's ALWAYS "lazy" with payments of bills?

honesty is the best policy so be honest and be true. It doesn't mean that you have to sound rude to tell a truth it could be done in a easy way.

Remind the valued client in advance when his/her obligation will due.When due date comes, the valued client shall have no excuse in paying his/her obligation.

Well if the client is lazy but is paying and the receivable from that client is not affecting the receivable policy of the company for the year then one option can be good and its that increase the credit period for that client.

but this should only be done in case the client pays atleast.

being lazy is not usually a huge problem, but this laziness should not lead to bad debt.

if you are feeling Lazy,Take a Break from Work