It's always better to ask what someone's opinion on a matter is instead of just assuming. It is between a person and God as to what that tithe might look like. And they should give because God has laid it on their heart, and because they want to be obedient to that leading.
God our church, we put 2 baskets in the back and put this scripture up on the power point
Malachi 3:10 ""Bring the whole tithe (tenth)into the storehouse, so that there may be food in My house, and test Me now in this," says the LORD of hosts, "if I will not open for you the windows of heaven and pour out for you a blessing until it overflows."
And we encourage people that above all else, their very life is their offering. If God has laid on their heart to give financially, they should be obedient. I get paid once a month, and on the 1st Sabbath of the month, my 10% goes in. And every week, I have my kids pray something to the effect of them giving their lives over to God, to be used by Him in whatever way He sees fit.