A lot of people don't but think about it. You buy a $500k property with an LVR of 80% which means you have to find $100k deposit. If you have these funds locked up in a property you are losing the interest on it.
$100k in a long term deposit could earn about 4% so it is costing you $4k to have that money tied up.
If you managed to start with a 100% mortgage that's a different matter.
... Which is why I believe that all cash-flow calculations should be based on the whole purchase costs -- buy price plus legals and loan fees -- and not just on the loan amount.
And yield figures for units and townhouses should include strata fees!