Herkese merhaba! 

I can´t seem to get a firm grasp on the usage of the grammar construction "-di -eli" (for example: gittin gideli). The example sentences that are supposed to make clear the rules seem far too confusing to me. In my final desesperation I have tried to come up with my own theory about the whys and wherefores of this grammar phenomenon. I would really like to understand it once and for all, so I wonder if someone can have a look at the sentences and the explanations I have created to illustrate my way of seeing this piece of grammar.

Basically we use it to convey the meaning of "since".

If the action since which something else has happened is POSITIVE, and the thing that has happened is NOT a DEFINITE amount of time but rather another action, then we use both the "-di" particle and the "-eli" particle in our sentence as well:

Çalışmaya başladım başlayalı sabahları erken kalkıyorum.

Almanya´ya gitti gideli beni hiç aramadı.

Babam emekli oldu olalı evde oturuyor.

If the action since which something else has happened is NEGATIVE, we use ONLY the "-eli" particle, no matter whether the thing that has happened is a DEFINITE amount of time or an ACTION.

Onunla görüsmeyeli yıllar oldu.

Seninle konuşmayalı sekiz yıl oldu.

Onunla görüşmeyeli çok şey değişti.

If the action since which something else has happened is POSITIVE, but the thing that has happened is a DEFINITE amount of time, the usage of the "-di" particle is optional.

Üniversiteyi (bitirdim) bitireli beş sene geçti.

Film (başladı ) başlayalı on dakika oldu.

Does it make any sense or not even close? 

Thank you very much in advance!

Toodles 

Seems to me that you get all of them right!

According to this post and as I got it, is that when the action is negative we don´t double the verb. 

Like we don´t say gitti gidmeyeli. 

Değil mi?

Bir adıl katılsam cümleye ne olacak?

Ben gelmeyeli çok zaman olmuş mu,

Benim gelmeyeli çok zaman olmuş mu?

Sen gelmeyeli çok zaman oldu = It´s been a long time since you last came, It´s been a long time during which you didn´t show up

With double negative:

Sen gelmeyeli çok zaman olmadı = It´s not been a long time since you last came, It´s not been a long time (period) during which you didn´t show up

Çok teşekkür ederim. 

One more question please. 

In this -eli form we place the period of time (if available) after the verb with -Eli suffix. Unlike -den beri or -düğünden beri in which it´s placed before. Right?

Like:

- Ben tatil yapmayalım 2000´de. 

- Ablam ve eniştem evleneli bir yıl oldu.