This is how we should always feel. Regardless of the many things we may already have accomplished or the high esteem we may already have gained, we should never forget that we are always in need of renewal.
The Church itself, already in a state of holiness for being the body of Christ, admits that it has to continually renew and purify itself. According to Catechism:
"The Church, ...clasping sinners to her bosom, at once holy and always in need of purification, follows constantly the path of penance and renewal. All members of the Church, including her ministers, must acknowledge that they are sinners.
"In everyone, the weeds of sin will still be mixed with the good wheat of the Gospel until the end of time. Hence the Church gathers sinners already caught up in Christ's salvation but still on the way to holiness." (CCC 827)
Thus, a Church institution that smugly claims its spirituality is irreformably perfect is an anomaly, and is, in fact, sowing the seed for its own self-destruction. It may have the foundational charism from the Holy Spirit, but it should never forget that it has sinners in her midst and, therefore, is always in need of purification and renewal.
And in spite of the original charism, the Holy Spirit may make more modifications of that charism due to the changing circumstances of the times. Fidelity to the charism is never a static affair, since charism itself is neither a static thing. It is always alive and continues to adapt to changing circumstances. And our understanding of it can always stand deeper improvement.
Of course, it goes without saying that any development on the original charism is always homogeneous. These are nothing other than a deepening and enriching of the original, not radically changing that charism. It is not meant to confine or restrict us to a certain way of life and doing things. It is always open to what the Holy Spirit prompts us to do.
This can somehow be gleaned from some words of Christ himself. "For them I sanctify myself," he said, "that they too may be truly sanctified." (Jn 17,19) Christ, who is holiness himself, goes through the process of sanctifying himself still so as to sanctify everybody else. Imagine that!
Sanctity and everything involved in it will always be a never-ending affair as long as we are alive. It will always demand something. It is the antithesis of the attitude that says enough to what the Holy Spirit shows us.
St. Peter also said something pertinent in his second letter: "Make every effort to add to your faith goodness; and to goodness, knowledge; and to knowledge, self-control; and to self-control, perseverance; and to perseverance, godliness; and to godliness, mutual affection; and to mutual affection, love."
We should never stop growing in our spiritual life which is a matter of growing in our love for God and others. We ought to feel the constant need for conversion and renewal.