The importance of 3D printing as a builder of the digital future is growing all the time. When it comes to the digital future, one clear goal is that, for example, spare parts are no longer necessarily shipped from factories around the world, but are 3D printed using a digital model of the spare part purchased from the manufacturer. Using 3D printers for replacement printing or home use is relatively simple. However, with 3D printers, you come across a wide variety of situations that require fault detection, troubleshooting, and general adjustment. This article highlights the most common problems with 3D printers. The technologies chosen for this study are Vat Photopolymerization and FDM (Fused Deposition Modeling) printing technologies because they are very common techniques for spare parts printing and home use. This study was conducted in concrete way, experimenting and producing problems intentionally, then solving them with solutions and techniques, which are common and gained through experience. As a result, this article is written as a guide to the most common problems with these chosen technologies. Solutions to the problems are showcased in simple and effective steps. After all, this study showed well the diversity of problem situations in 3D printing as well as the need for concrete expertise in troubleshooting solutions. The problems faced and tackled in this study were the most common ones but there can exist other problems too.