No, window installers do not need to come {inside|indoors} {to do|to perform|to carry out} the {job|task}. {Most of|The majority of} the time, they will {just|simply} need to {use|utilize} a ladder to {get to|reach} the window. {However|Nevertheless}, if the window is {high|very high} up or if there are any structural {concerns|issues}, then the installer {may|might} need to come {inside|indoors}.