Depends on who, how often and how long the commitment. For me it is a trade off between flexibility and cost. For you it is a trade off between uncertainty and cost. I trade my flexibility for your certainty and the price depends on how much we each value those things. I would not want to see the same provider more than once every month or two but would make a commitment for about 20-25% off regular rates. Say, commit to 6 times over the year for 20% off. If the discount is not 20% or better I would just stick with regular rates and keep my flexibility. Others might be willing to commit more, maybe once a month or more, but then might want a bit more discount.

This is akin to a high end car lease. $650.00 a month, your limited to the number of miles
you can drive it, you have to turn it back in, in the same condition, less wear and tear,
you have to pay for dents and dings, it is guarenteed to turn on and off when you want it to
and take you for a ride whenever you want. together you can see the usa and you
should  do regular oil changes! why just sign me up...we should talk!

Some ladies do provide a frequency discount based on a certain amount of visits. Keeps ya cummin back fomo. I think your idea is different. Sounds good too.