upper age restrictions in applying for teaching jobs abroad

I am an experienced, licensed, retired, elementary education teacher with an endorsement in ELL. I realize that in the US it is improper to age discriminate, but I am interested in knowing what the upper age limit is for TeachAway given that some countries will not offer a work VISA after a certain age and thus my applying is a moot point. So at what age do you recommend applicants no longer apply? Thank you.