Waiting for a toilet seat to be delivered is really more efficient than getting one in the mean time while you’re already away from home in your car? Or out to dinner near the home store?
Only IF you drive and it’s the only thing you go shopping for and the only reason to drive.
If you really can’t plan your shopping trips efficiently then, maybe.
Walk. Bike. Stop on the way home from work.




I don’t think it’s unreasonable to want to avoid your MIL. I also think it’s reasonable for your wife to maintain the relationship.
Can you use her visit as excuse to take a vacation—alone or with friends—or visit your family? Given the circumstances, I think avoidance is a perfectly valid option. Get some you time if your wife is cool with it.