I was under the impression that たら was used for "if this then", statements. Be they cause and effects or when statements. Whats the difference with と?
と is restrictive. Used only when something naturally leads to something else.
"Something naturally will cause something".
- この業界で働くと口がうまくなる。 (When one works in this industry, one (naturally) becomes good at talking.)
たら is often used when the instigating reason or cause brings about a discrete change. The change happens, and then after that, the second clause. There is emphasis on the cause happening and then soon after, the second clause.
"If this thing happens, then after that thing happens, something"
- 自分のクレジットカードを失くしたら、すぐに報告してください。(If you lose your credit card, please report it ASAP)
Between the two, only たら can be used as a true conditional (If one does X / If X happens, then Y). と can only be used as a conditional in talking about a generality (If one does X / If X happens , then naturally it becomes Y).
Source: a conditionals guide I wrote