Now.
Yes, it's a cliche, but allow me to explain why it holds true in all markets.
In our business we love property values that grow quickly because it builds our portfolios and makes our investors happy with their decision to purchase. The flip side is that while this is happening the demand for property is good and developers offer less discounts which means you need more money to invest in property and therefore less people want to invest (or at least the sales are more painful for them.)
The trick is to view a constant return that you will achieve.
So - when developers give you the big 15% discount, the market is probably stagnant, so you'll see a net return of 15%. But when the market is galloping, your capital growth will be at say 7% and your discount will be lower at say 8%-10%. Your net return may be around 15%-17%.
Either way you are making around the same return even though you might not see it.
Of course, this is a massive oversimplification since there are so many factors that l have overlooked but the important thing is this: you are going to need to invest some money. How much will depend on the market and the structure.
If you buy in a stagnant market then you get in cheap but you have to cash flow the ongoing costs so it's good for your capital and bad for your cash flow. If you buy when it's a hot market it costs you more capital but because of the growth your cash flow is better.
I hope this explains why the answer to the age old question of 'When should you buy?' is always Now, today, right this moment!!