In reality (not in the model), spools on site for a long time (at worst, a spool could be the first one delivered and last one installed) are more likely to sustain damage. Additional preparation work (e.g., erecting scaffolds or, at least, checking if previous preparation work still meets specifications and if there are no new obstructions) may be required when installation crews finally move into an area where work is to be completed. Real project costs are incurred for keeping track of and re handling materials on site, for working in obstructed areas, and for performing out-of-sequence work.