Raising the rent should be a standard practice when a lease is up for renewal with the current tenants or when you have a turnover of tenants.
I try to raise the rent 2-4%. However, it’s also a very influential bargaining chip, and should be played appropriately.
When you have a stellar tenant (one that pays on time and maintains your property), you should try your best to get him/her to renew the lease. A quality tenant is far greater than a 3% raise in rent. Eventually, they will inevitability leave, and you will always be able to raise the rent for the next tenant.