Housewarming gifts are tricky. They are tricky by scale: larger than a host gift, smaller than a wedding gift. And they are tricky by kind: housewarming gifts should be practical and also personal both to the person giving the gift and to the household receiving it. As I reach the home stretch of my 30s, I’ve noticed that some people develop their own trademark housewarming gifts. My mother — famous in the family for her salad dressings — inevitably gives a bottle of her favorite balsamic vinegar and a mini whisk . One good friend of mine always shows up at housewarmings with a top-of-the-line first aid kit — a gift that always seemed a bit grim before fires ravaged Los Angeles and it took on an air of good-neighbor poignancy. (The only housewarming gift we’ve been able to agree on as a society is, I believe, one of the worst gift choices there is. Why we feel so comfortable giving living plants as gifts confounds me.…