Updated: Sep 10, 2018
Every property is different so there is no set rules here. What you need to consider is that if you spend a certain amount of money on your property prior to putting it on the market, will you get that money back? For example, if you spend $20,000 renovating your kitchen, will that get you an extra $20,000 or more when you sell the home? If you spend $50,000 for another bedroom and ensuite, will you get $50,000 more when you sell the property?
Generally the answer to these questions is no.
Presentation is key when selling your property, so items with great value are things like painting, or tiling. Perhaps rather then renovating a tired kitchen, updating the bench top and the cupboard handles will get you a better return on your investment. A good agent should be able to walk through your property and advise you on the items that will have the biggest impact on selling your home.