Next time I'll start with the engineer.  

These systems are becoming more sophisticated and (my favorite) capable, leading to improved user experiences and potentially freeing up human employees to handle more complex tasks and interactions.

Sometimes I had to beg for extensions because I couldn't finish tasks on time.

., electrical, plumbing).Project Timeline:Start Date: For the portion of work they are completing.Completion Date: Set realistic deadlines for their tasks, adjusted to your overall project schedule.Liquidated Damages:Specify a daily amount to be deducted from their final payment if they fail to meet deadlines (with exceptions for factors beyond their control, like severe weather).

They found it out, andI had to go to the planning board and zoning board, hire an engineer and architect to make the fourth unit legal.In my opinion, the realtor should have verified the zoning, and if you used bank financing, it's pretty rare for the bank to miss it as well.You are probably going to have to hire an architect to draw plans and to get it approved as a triplex.I wish you luck.

No, DIY is not the same as a virtual site visit or a study done by engineers @Dana YobstAs @V.G Jason said, you could very likely cost yourself more in time and money.

You may have to search a bit for the right contractor or engineer - sometimes I see one solution dominating in an area - "that is how we always do it" 

This used to be a near-impossible task for a company like BiggerPockets, but technology and 3rd party solutions are getting better.

Whether that is most contractors, hiring an engineer, or getting self-educated.

These methods include: Detailed Engineering Cost ApproachDetailed Engineering Cost Estimate ApproachSurvey or Letter ApproachResidual Estimation ApproachSampling or Modeling ApproachExperience or “Rule of Thumb” ApproachIt’s important to understand the differences between the approaches including which one best fits your property and the reliability of each approach.DETAILED ENGINEERING COST APPROACHThis approach compiles the costs from construction and accounting reports to build a report.