Just apprecoation mails, no incraese in terms of money or so, Is it enough?

Appreciation mails are nice, but they don't pay the bills. I think companies need to offer more incentives (money, paid vacation, etc) to keep their employees with them.

i am not sure what kind of appreciation mail you mean here, but... i think over here in my country.. an appreciation letter from the management - does become a 'good reference' or support letter when you submit it together with your application for a (new) job. i serves like some kind of prove that you have achieved something or were involved achieving the company's goal in a certain project... since the new 'employer' may not know you at all.. these letters do help them sort out the 'team players' and 'achievers'... still... i do prefer 'monetary reward' because i dont think i'll be searching for any new job until i retire....