When setting your offer price, you should consider the amount of time a house has been on the market. Typically, the length of the time a property has been on the market directly correlates to how much you should/could offer.
The longer the property has been on the market, the lower you can bid on your offer typically be. It implies that, contrarily, if a house has been put recently on the market, your numbers should be higher on offer. If you try to undervalue a newly listed property, you risk the seller handing on your offer in favour of another opportunity.