Is there any reason why I should not regularly choose the low bidder?

Now this may seem like the logical thing you should do, but emember that cheapest is not always the best value in the long term. Your house is most probably your biggest asset, and in Perth, with real estate rices escalating, the quality of paint job, and the appearance of your house an make a huge difference to its value.

This is not something you want to risk a shoddy job ith.  Spending an extra 10 or 20% for a quality job may well be an xtremely worthwhile investmenent.

Any painter in Perth can start a job. It takes a professional with the proper budget to purchase the best materials, pay his overhead and leave with a satisfied customer. Most likely the low bidder won't be around when there are complications or you need customer service. Remember, you get what you pay for.