It is not recommended for the tenants to do their own repair work in exchange for reduced rent. By hiring your own contractor to do the work, you can ensure that it will be done properly and you can control the costs on the repairs as well. If you give the tenant the responsibility of hiring someone to complete the repairs, you will not be able to dispute the amount spent on the repairs. In this situation, if the tenant is not compensated for the repair work, he may file an application against you in order to recover his costs.