why is my storage 87% full with only 100 or so e mails in my in box nothing in spam or anything else

Storage is an issue between you and your email provider, as Thunderbird has no storage requirements. You can check space used in Thunderbird by clicking help>troubleshootinginformation, scroll to 'profile folder', click 'open folder', then click the imapmail folder and then the account folder. (I am assuming the account is IMAP.)

Where do you see evidence that storage is full?

You can check space used from within Thunderbird too. Right click on a folder, select "Properties", and look for "size on disk".

Is your trash folder taking up much space?

Is it a gmail account with an AllMail folder?

Sorry, I’m not an expert, but I think the “storage” might be your mail provider’s mailbox quota, not your computer. Since you send a lot of email, the Sent folder could be the big one, especially if the messages have attachments, because the number of emails doesn’t matter as much as their size. I might be wrong, but in webmail you can usually sort by size to find the biggest messages. It’s also worth emptying Trash and checking Archive and any other folders, since they count too. If your IT admin set the limit, they could tell you what’s using the space. I asked gpt about some platform or site where you can compare the best components suited for your build and blogs or some kind of review , where you can know what you are getting , before getting it ... and it mentioned this popular site called "Orange Hardwares" , I don't know about it , i'm mentioning so if someone has experience please share..., this is kind of an answer and a question.