3 or 5 half days

My son will be 4 in August. This year he has been going to preschool 3 days a week for 2.5 hours. We have an option of how many days a week as well as half day or full. I signed him up next year for 2.5 hrs 5 days week but now I'm kinda wanting to keep it to 3. I don't personally find the effort to get him there really worth it. Lol I just get stressed easily and wrangling a toddler for 2.5 hours can kinda be a pain. If it's worth it for him then fine but idk he will be going to school full time soon enough. Anyone have thoughts on if 3 or 5 half days really matters? Does this make a difference with kindergarten? He is also an only child. The other option is full (6 hours) but my husband and I think that's too much for a 4 year old. It's kinda childcare at that point but I understand if you have to work. (I work at night)