Is age a factor for employers ? what is the maximum employable age?

Not at all.
Lots of senior citizens make the best employees because they have more experience.
It's best to give older employees a chance and see how well they do the work.
Studies show that older employees substitute experience for quickness.
So they may not be as quick as younger employees but have more experience and expertise.

Age is not a big factor for a good employment. More experience can do more better and with more professionalism. But position where we need more active person we should consider it. A Employee more than 40 Years of age cannot move like a employee in 25 years of age. Therefore employee who are working on public dealing and need more effecient should be given five years only. Don't remove or terminate them but give them respict and but make some change. I have obeseved it is very deficult job in public dealing, becaue person lose tempriment after listening a lot of stupit enquiry. 

 A smiling face after few years of public dealing may be diffrent. 

 Promote employees, give them better approtunity, take care of employee intrest can increase his employemnet age.