The Invoices starter solution doesn't do a very good job of managing inventory levels. It's easy for user errors to either not deduct the quantity sold or to deduct the amount sold more than once for a given invoice. I haven't looked at this recently, but I seem to recall there's a field in the products table that controls whether or not it is an inventoried item...
What do you want to see when you "post" an invoice that isn't taking place with this starter solution?
More about stock levels than anything, effectively uintil it's 'posted' as such it shouldn't affect my stock level as until then it's just a quote or pro forma. Once it's posted the job is effectively out and the stock should alter.
I haven't done too much work so far, would you perhaps recommend a different starter solution for me? I need to do the following...
Manage stock of rental equipment
Do quotes for clients
be able to pull up a piece of equipment and see whether it's availalble and where it is.
Is there something similar?
Don't know of a starter soluton that does this better. I think there's a button in the invoices starter solution that has to be clicked to update inventory. That handles the "posting" issue, but it's very easy to forget to click this and there are no safe guards in place to keep the user from clicking it more than once.
You'll find a number of threads in this forum that discuss an "inventory ledger" approach. This method modifies the line items table to function like a ledger where items received into inventory are "deposits", items removed from inventory are "withdrawels" and summary fields then compute a running total so that you can see the quantity on hand for every item and also see how your inventory levels change over time--which can often tell you useful things about your inventory levels for each item and what re-order points you may need to set.
Don't know if this is an approach that appeals to you or not. It would require performing surgery on your invoices starter solution.
To handle the "posting" issue, you can add a field to such a table that recieves a 1 when the line item is posted. The calculation fields in this table can then ignore non posted entries when computing a balance and a script run from the Invoices layout can update this field for each line item to post them.
The other option is to figure out how the Invoices starter solution works and then modify the scripts to make sure that you can't post items twice and then to modify the layouts so that you have a visible indicator to tell you whether or not the item has been posted.