Big Changes and Breadcrumbs - a slice at a time

Or wait for the whole loaf?

[LizaJane]

I have a site that is well over 10 years old - over 1500 static html pages. For years the site ranked (usually within the top 3) for several hundred keyword combinations. I have noticed a mixed bag of retaining rank / drop in rank on some searches over the last year. Usually the drop ranked page has multiple widgets on same page plus no breadcrumbs, while the competitors are placing a single widget per page and using breadcrumbs. Easy for them - most use flat file databases.

Besides the SEO aspect, my site could stand to have breadcrumbs for a navigational point - product nav is at the bottom of the page! ( Yes, way old school)

I am currently working on adding some new product pages. Easy to add breadcrumbs to the new pages, will take quite a while to add to the whole site. Also, a bit nervous about how it will affect ranking for old pages. Will search engines see the changes as over optimized?
Should I :
1- Put up the new pages ( about 300) with breadcrumbs and see how they do? (But confuse the visitor as it would not be all pages)
2- Put the breadcrumbs in comment tags for now and wait until I can upload the whole loaf?

I am considering moving product to separate category pages. Many hundreds of page changes. Very concerned about losing page rank - will SE's think duplicate content even if change is made seamless?

3 - Should I separate out a few widgets to their own page and see how it goes?

[tangor]

An eye for SEO is always necessary. However the EYE should always be for the VISITOR. If these changes improve their experience then you can bet that the search engines will see it the same way... eventually.

It's one thing to get folks to the site. KEEPING THEM THERE is what it is really about. Make that happen and no worries. The rest of it will follow.