See buddy any bank before giving you a loan first of all analyse your income status,your job status and what can be your further growth as well as for how many years you can earn.In other words most of them take it this way:-
If you are 40 and your monthly salary is 50k.
Now you want a personal loan of 20 lac.
Bank will first of all analyse if you have any other loan,if no then okay and if yes then they will deduce its installment from your monthly salary for the term of loan.
Example:You pay 15k as home loan installment and its term is for next three years remaining.Then they will consider your salary as 35k for next three years.
Now they will make analysis of other loans like education loans of your children in which you are guaranter etc etc and again make slight deductions.
They will also ask you to submit a copy of your salary slip(latest) and the form 16 of all the tax-paying members if the family and hence will calculate and conclude that how much maximum amount will be safe for you as well as them to be given to you.
In other words,when they give you a loan at 40,they will consider you working till 60,hence you can take it for maximum 20 years and minimum 6 months(before 6 months you can't pay it back).Now they will decide if it will be safe to give you a loan of 20 lac or not and you have enough assets or job security as a guarantee that you can pay it back.
About banks,I'd say that if you want the loan to be completely hassle free then take slightly extra pain and go for SBI.They will surely get a pair of your shoes broken but then they will let you live with ease even if you are unable to pay an installment or two in future.
And at last they have least number of "CONDITION APPLY"(*) stars too and the complete deal is transparent.
All the private banks give loan with smile and when you pay it back then you get many surprises,so be careful with HDFC.
Have a look at this thread:-EMI Problems - Not Received My Salary