1) Growth. Here you are growing and hiring. You have figured out how to make money and are doing it as fast as you can. Even if someone is bad at their job, they already know how to do it - so you simply let them keep it while everyone else is promoted. They have to really screw up to get fired. Business wise, every decision has to be profitable - but if you got a good product that can be easy to do because you have no real competition.
2) Expansion. Here your business has thrived and succeeded, but it needs to expand beyond the original offerings. Business wise you can take risks. You are now competing with other companies but hopefully have some edge. Maybe you add new products, maybe you go international. The difference between growth and expansion is that you are trying new things, not just teaching everyone how to make money your way. You might actually fire people here, but not a lot. If people keep there head down, they are pretty safe.
3) Mergers. Here you start buying innovation rather than starting it in house. Your expansions are no longer working, perhaps because they do not fit the brand you have created. Decisions are now accounting based. X companies has a greater return on investment than yours does but is small enough for you to buy out. You often fire people after a merger - either your old employees who are not as good as the people you bought, or the people you bought who are as good as the ones you already had.
4) Cost Cutting. Over time your growth and expansion moved so fast you developed some expensive practices. You got your business down, but now it is time for some corporate decisions. Buy the cheaper packaging. Raise expectations - and fire those that cannot meet them. Which expenses are truly necessary and which can be replaced with cheaper options. If you cut the wrong costs, you destroy your brand quality and reputation. If you cut nothing, your competition starts stealing your lunch.
Almost all companies go forward, from 1 to 4 rather easily. But it is very hard to go back a phase - with one exception. If you have grown large enough and saved enough money after a cost cutting phase, you can go back to mergers.
The worst part is when some idiot thinks they can go back to expansions - come up with in house ideas that are better than other companies. This almost NEVER works (unless you fired one of the founders - then you can hire him back and pretend it is not a merger). Why? Because you are already a big company - with all the bureaucracy the Mergers and Cost cutting created. This slows you down and a new expansion has to be incredible to make a difference to your large balance sheet.