"I charge storage to each client and calculate it by hand"

Storage is sold as a service per pallet per month and quoted to each client with its tax.

"I don't know which stock level each client has agreed with me"

A minimum and maximum quantity for each client's product, recorded in a reordering rule.

"Nobody warns me when a client's stock falls below the agreed minimum"

An automation rule that, when a client's product falls below the agreed minimum, creates an activity for the person in charge.