Permit everything. 

I'm surprised short-term rental regulations and permitting agencies would even allow such a business model.   

He did about 20% of the work and didn't pull the permit.

I often deal with newbies so they tend to make these mistakes:1- underestimate the time rehab will take, often due to weather delays or delays with local officials securing permits or delays with local building inspectors coming to inspect rough-ins thus delaying installing drywall and finishes2- Over improving the properties by building them out as if it were to be their personal dream home, which means they go over budget and eat into any profits from selling plus cause more delays with changes3- Over price the flip so it sits on the market too long and their carrying costs sky rocket which eats into any final profit4- under estimate monthly carrying costs like water service charges and garbage collection charges- these will still be there even though water may not yet be turned on and the cost of electricity the contractor needs and will use monthly5- get in trouble with the local building or planning dept. due to over building on a lot or tearing down so much of a house as to then have it viewed as a new build that doesn't meet todays lot line set back requirements and then have a stop work order issued for months while they argue that its not a new build which only increases carrying costs and decreases future flip profit or really causing the profit to become a lossThe ones I see most successful are the first timers who buy a 3 or 4 unit to rehab and reside there for 12 months and do it on an FHA 203k loan to be honest.

I'm following the steps in the link below.https://medium.com/keycafe/und...Anyway, I'm making progress but now hit a bump in the road in trying to get my "certificate of use (CU)"; so for me to get this I first need to submit a building permit application for remodeling requesting a "change of use" to "condo-hotel". 

All construction was done with permits, and all new bedrooms are up to code according to size/placement/etc of egress windows, doors, closets etc. 

@Chris Iley, If you want to be 100% sure, ask your local permit office.

Many jurisdictions will permit a title transfer to be carried out without any transfer/deed taxes or fees if the beneficial ownership of the property is identical both pre-transfer and post-transfer.  

Without the permitted space, there is a good chance if you try to sell, the next buyer might realize it. 

Could someone explain why there would a huge difference in price per Sq ft between say Natick vs Wellesley or weston vs Waltham in the absense of permitting fee.