If you are seeking a seamless solution to merge your Outlook inboxes and sent items then you should read the blog "Outlook combines inbox". It offers two methods to merge Outlook inboxes and sent items. However, it emphasizes that the Professional method surpasses the manual approach due to various limitations of the manual method.

Therefore, the recommended tool, Sysinfo PST Merge Tool, stands out for its efficiency and versatility. It effortlessly combines multiple inboxes and sent items files, with the added benefit of merging calendars, journals, and other mail items into a single folder. Its user-friendly interface and date range option simplify the process, while it remains compatible with all Windows OS versions. 

Additionally, the tool efficiently removes duplicate files and more.