There are projects that are well suited for DIY work, and there are others that are better off being done by professionals. Many DIY enthusiasts fail to realize this and often end up exhausted and frustrated with a lot of unfinished work on their hands.
Installing glass shower enclosures is one of those projects that most people will want to leave to professionals. Although the job seems relatively straightforward, there are many factors that have to be considered, and some can only be learned through experience.
Misfits and Misalignments
Many people know what it's like to spend hours or days only to realize once the work is almost done that something somewhere is either misaligned or just doesn't fit. There are many reasons why such issues occur including:
You may have taken the wrong measurements when initially planning the job
The factory or shop may have sent you the wrong item or part
One or more parts may have been damaged during the installation process
You failed to consider all the necessary allowances
A single misfit or misalignment may mean having to start from scratch, and this is the kind of problem that professionals avoid by preparing adequately and ensuring they're using the right parts.
It's a lot easier to damage parts of your shower enclosure than many people realize. When you're working with a material such as glass it can break for any number of reasons including:
Being dropped even from a small height
Being subjected to an uneven force (e.g. bending)
Tightening a fastener too much
Replacing a damaged part of your shower enclosure can be surprisingly expensive. Although there is no guarantee something won't get damaged if the installation is done by a professional, at least they'll have insurance to cover such incidents. Additionally, they are probably better at handling such items.
Your shower enclosure may come with a manufacturing defect that causes a part of it to fall apart during installation. If the issue is the material or the workmanship, you'd think that it would be easy to get the company to replace the part.
Unfortunately, many manufacturers have policies that state the warranty is only valid if the person who was doing the installation is a professional that is licensed, bonded, and insured.
Regardless of how obvious it is that a part was defective, a voided warranty means no free replacement.