The play time I would say is a direct correlation on if you plan to play to just play or if you are actually trying to achieve goals. I have over 100 girls added for example, and the clothing mod and video expansion really increases the game size and replay substantially. I am even expanding my clothing mod. As of now its over 1000 images and I should have about 500 more videos on the next release. This game can be played for an hour, or as long as you want. It can be goal based, or just a sandbox. I personally go with an hour long or so session to work through some girls then end it. Its sandbox, so I dont do much with the mothers, rules, etc. Thats the great thing about sandbox games IMO, but it isnt for everyone.
I would suggest you download it and be sure to get some mods ... shameless plug for my clothing and video expansion mods. I think it greatly expands the variety and playtime. I really dont think you will be disappointed when you give it a shot. This thread is also quite active when compared to others so plenty of folks to help you if you are stuck on something. I also think BolHex is being humble. For sure there are areas to work on, but IMO they are polish and QoL type things. This is better put together than a lot of full release games I have played.