When our son graduated from college, my husband and I bought a small condo for him to live in. He pays us “rent” and we pay the mortgage and taxes with that. Recently, he told me that his girlfriend of one year would be moving in with him so they could “save” money since she spends more time at his place than at hers. Do you all think it would be unreasonable for me to add a rent increase since she would be moving in with her dog and cat and the wear and tear on the carpet, appliances, etc. would be on us. I think a rent increase is justified but some close to me do not agree and think I should just let them live together. She was currently paying $500+ monthly on her place so in essence that is what they would be saving. I haven’t heard any talk of marriage plans in the future. Our son is 27 and his girlfriend is 26.