Kevin MacDonald is already braced for the up-and-down nature of being a manager after declaring his interest in replacing Martin O'Neill.[LNB] MacDonald has informed Villa owner Randy Lerner he wishes to be considered for the post on a permanent basis after operating for three weeks and five games as caretaker boss.[LNB]The former Liverpool midfielder made his decision in the aftermath of Sunday's 1-0 win over Everton.[LNB]Lerner has been full of support for MacDonald and put him under no pressure to make a quickfire decision.[LNB]But MacDonald is under no illusions as to how quickly he could go from hero to zero given the pressurised and results-orientated nature of modern-day football.[LNB]He said: "I know that managers, from week to week, if they win a game they are great.[LNB]"But if they lose a game everybody dissects it. I know how tough the football industry is.[LNB]"Every time you appoint a new manager it is a major decision at any football club.[LNB]"Are you getting it right, is it going wrong?[LNB]"You only get something like three games in the Premier League don't you and then you are a terrible manager?[LNB]"So every time you have to appoint somebody, it is a major decision."[LNB]MacDonald admits he thought carefully about putting his name forward as a candidate to take over from O'Neill who quit five days before the start of the new campaign.[LNB]He said: "I'd like to think that I actually think about all things, whether it is football or anything.[LNB]"I was not naive in thinking this was going to be an easy decision to make.[LNB]"I am aware of how big a decision this is.[LNB]"But the staff here have been fantastic. They have been very, very supportive and they are all keen for me to want to be involved.[LNB]"When I've spoken to family and people like that, they have always said 'make your own decision - but you have worked hard to get to here'."[LNB]MacDonald has the support of senior players such as skipper Stiliyan Petrov, Luke Young and James Collins who have all spoken publicly about their admiration for him in recent days.[LNB]He has been a key member of developing a crop of promising youngsters as Villa's reserve-team coach.[LNB]But his only other experience of senior management when he temporarily replaced Brian Little after he left Leicester in the mid 1990s.