Does being heavenly minded mean you're no earthly good?
No. While believers' desires and friendships may change, they are not to become so heavenly minded that they are no earthly good. They still function, work, and plan, and Scripture permits accumulating wealth and caring for family when done within God's timetable and plan.
Les explains that when a person becomes a believer, friendships and desires often change because the believer now belongs to a different world. But that change does not mean becoming so heavenly minded as to be no earthly good. Believers still function, work, and plan, and there is nothing wrong with those activities. Les also notes that accumulating wealth or an estate is not inherently wrong, provided it is within God's timetable and plan. Paul likewise teaches that family should be cared for, with parents laying up for children. This fits the truth that all things have passed away and become new, and Romans 8:9 describes believers as not in the flesh but in the Spirit, if the Holy Spirit dwells in them.