Kwikee has a spray white grease that does a great job.
I got this Blaster product for bike chains and it works well on steps too.
Annually is plenty. I did WD-40 and steps worked for years.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB