Generally, mixed use expenses for a trade or business are prorated based on the business use.85-90% business use year-round for your only laptop seems high if you only own one property.Some things you're considering "trade or business" related might not be. 

Dave, I love the show and the round table discussion format.

Of course, I was very nervous on the first go round. 

They will fail you for the smallest of things and I have actually been told by the inspectors that they are expected to give a fail first time round or they are not considered to be doing their job right.

Granted, that calculation is just with simple interest not compound interest, but it should be sufficient to get the idea.For example with round numbers, let's say you have $100,000 to invest at 3.3% -- that's $3300 of simple interest. 82.5% of $100,000 is $82,500 and 4% of that is also $3300.

I've just sent out my first round of mailings to vacant land owners.

In need for all rounded builder with foundation experience...

By the time you get through 4+ years of a standard University education, you should be well rounded enough to get the job done.

Would be about $40/round trip in expenses if allowed.

They sell a rounded stair that you can stain and then put that on the tread/landing/flat part of the stairs.