Sue and I reached an agreement 25+ years ago when we became empty nesters and the disposable income shot up significantly. I don't ask her about what she spends on golf and she doesn't ask about my tools. The only corrollary to this rule is that if the joint account is to be used for any amount over $500 notice must be served that a purchase is to be made. Since starting Chester Toolworks as a side business 7 years ago none of "our" money has been used to buy tools. Having a woodworking related business has great benefits. We have always been honest with each other and I have never tried to sneak a tool into the house. Spousal presents yes, but tools no.