Construction delays are a normal part of running one of these businesses. One thing that reputable contractors have going for them is that they don't let regular events that might delay the project have any impact on the clients. Because they should have plenty of experience with these delays, they should be able to work the ones they expect into the contract.
Some of the most common reasons for delays in construction can be handled by the contractor, but others are out of their control. Having contingency plans in place is beneficial and can help keep the clients happy.
One of the biggest issues that can come up that is out of the contractor's hands is the weather. Building in some bad weather days into the construction schedule is necessary. If possible, they should have a plan to work on indoor projects or ones that can be done despite the rain or other inclement weather.
Another issue is having overbooked subcontractors or workers. This can make it difficult to get jobs done. The problem is that there are times when projects are stalled out as long as the subcontractors or workers haven't finished their specific duties.
Improper budgeting can also make things difficult for the contractor and might delay a project if they are having to wait on money to come in to get something done. This can mean that vital supplies aren't getting ordered on time or that subcontractors aren't being paid and won't come out until they are.
Typically, you won't mind if a project finishes early, but you will be upset if it takes longer than the contract states it would. Know what the contract says and be ready to take action if there are avoidable delays that are costing you money.