Scobe's Quick Tip #67
There are only two types of slot machines where playing maximum coin is absolutely essential--the giant, linked progressives such as Megabucks, Quartermania, and Wheel of Fortune, and the "buy-a-pay" type machines where extra coins open up more winning combinations.
You never play one or two, or less than maximum coin on such machines since to do so gives the house a rather large edge.
For more information on slots read Break the One-Armed Bandits! by Frank Scoblete, The Slot Machine Answer Book by John Grochowski, and The Slot Expert's Guide to Playing Slots by John Robison.
Scobe's Quick Tip #68
The slot machines that tend to have the highest return, other than the ones that are guaranteed to be 98 or 99 percent-return machines, are generally those that have no bonus rounds, progressive features or brand-name affiliations.
For example, Double Diamond and Wild Cherry are two "stand-alone" machines that fall into the preferred category.
For more information on slots read Break the One-Armed Bandits! by Frank Scoblete, The Slot Machine Answer Book by John Grochowski, and The Slot Expert's Guide to Playing Slots by John Robison.