Is it always advisable to take out a mortgage when buying investment property or not?

When buying land as an investment property, is it advisable to buy it cash if one can afford to or is it alway better to get a mortgage?
Answer
If you want to build a credit history, then taking out a mortgage is a better option. in addition, i believe that the interest on a "buy to let" mortgage can be off-set against tax.if you have the cash, are only buying land for the future and do not need to build a credit history, i would always advise against any kind of a loan. why pay interest when it will eat into your profit?