When should I start looking for tenant

[Patrick Young]

I had been given about 6 months notice my 4 year tenant is moving. They leave July 21. I started advertising June 1 for August 1 move in. Is this too early? What is the etiquette to my current tenant for showings? I don't want to hassle them for 6 weeks. I am already getting requests to view the house. If I do get a new renter soon do I collect any non refundable money now to protect me if they decide to not move in at the last minute? Last time I rented the house was vacant.