yes, if your goal is to maximize your payout % on slots

if you are gambling and not trying to maximize your payout - many gamble for entertainment (crazy to me, I accept it as fact that it works for them) then decide what works for you.

No. It depends on the kind of slot you are playing. Look at the paytable. If the best jackpot pays more for betting the max or if it is a progreessive, then you should max bet. For newer video slots, it is usually better to pay max LINES and bet per line according to your budget and risk tolerance.

Try checking out this article:

…casinocitytimes.com/articles/17416.html

Always, always bet max on any progressive that says the progressive is only paid out with max coins in. How bad would it be to hit the winning combination and have to settle for a few hundred rather than a million or a car? Other than that, it depends on your bankroll and your expected outcome. If you are there to win big and not just to have some entertainment, you will probably want to bet max. More risk you take, more payout you get. However, if you are wanting to be entertained and any wins are just a bonus, then you do not need to bet max. If your bankroll allows you to bet max on all games, then good for you, but you will want to check carefully what the max bet is before hitting the button. A simple 9 line nickel machine with a max bet of 5 coins per line is still $2.25 a shot. However, when you get a 20 line game that jumps up to $5.00 a shot. Of course, there are machines that are less, as well as, more per max bet.

A lot of the Multi line penny slot's the pay table doesn't change with the amount played. So check the pay table.