How often do you change titles & backlinks

Noob questions.

How often do you refocus your page titles - I set mine incorrectly and then changed them to be more focused and now I’m waiting for google to re-index. So does google remember how old that page title was or is this irrelevent? Do established page titles attract more respect than ‘the new kid on the block’?

Basically I’m waiting for google to re-index one of my shop category pages so i can go for a backlink campaign. My backlinks will be in ‘follow’ forums - am I right in understanding that forum backlinks are like fruit - they go off with age?

Once its all under way can I get an instant measure of my backlink or does this too take time to bubble up the results pages?

I know I want to set and forget and come back to it in a few months but that cycle of experiment is too long for me right now.

forum links have next to no value to the search engines to start with since the relevance of the forum posts to the page you link to is not going to be all that great.

Forum links are most useful when the threads you get the links in are actually related to the topic of your page so that some of the real people reading the thread will be interested in following the link.

If you want backlinks to have decent value to the search engines you need them to be on web paes that the search engines already consider to be authorities on those topics.