As a REALTOR(R) in Saskatoon I see a lot of properties and a lot of renovations. It's sometimes quite easy to figure out which renovations were hired out professionally and which were done by an amateur, aka the home owner. I have nothing against saving some hard earned money and doing the work yourself; I do the same thing as often as I can, but I do know my own limitations. There comes a point when the value that you are trying to invest into the renovation is minimized by the poor workmanship of the final product.
For example, I was in a home today that stated that it was "completely renovated". Great selling feature when done right, but in this case, it was a lot of money spent on products that were installed poorly. If I were a potential buyer of that home, my thoughts driving to the house would be "wow fully renovated home, awesome!", until I entered the house, where my thoughts would quickly change to "wow this is a lot of nice materials that I'm going to want to throw away and replace".
Of course there may be people who aren't as picky on finishes and will buy the house as is, but the vast majority of buyers want to see things done right. It puts a tiny thought in the back of your mind of "if it's this bad on the surface... what's behind it?". So all that money you put into the products, time you put into the project, just turns into a giant doubt in the Buyers mind of the condition of the entire property. I'm not just talking about glaring, obvious problems, such as missing trim or broken tiles. It's the little things like improperly finished trim, poorly cut-in or masked paint jobs, and separated laminate flooring. All the little things add up to a large doubt!
In the end, if the renovation project is beyond the scope of your abilities, you will gain much more equity out of the completed home by hiring a professional, than if you do the job poorly yourself and have someone else rip it out and do it right! Not to mention, you will enjoy the final product a lot more when it's done properly and completely! (I can't count the amount of houses I've seen with incomplete renovations, which is a totally different topic). Your home is your investment; make sure you invest your money and time in the right places to maximize the return on your investment and know when to hire a professional!