From Divine Intimacy, Fr. Gabriel of St. Mary Magdalen O.C.D., comes this insight for Lent:
If, after renouncing the superflous, we still remain attached to them by affection, our material renunciation will amount to very little. "For it is not the things of this world that either occupy the soul or cause it harm, since they enter it not, but rather the will and desire for them, for it is these that dwell within it" (St. John of the Cross, Ascent I, 3,4).
This should help make it clear to us, that it is not the giving up of a good we are attached to that is our goal, but to sever the attachment, for it is the attachments in the soul that obstruct our attachment to God. Do we not give up a pleasure during Lent, and even struggle to be faithful to that decision, but desire it the whole time, and return to it at the end of Lent? Do we not over the Lents of life, learn how very hard it is to hold ourselves back, the struggle within being waged? Do we ever manage to give up something and break the attachment to a good in itself, then never returning to it again? Yes, it is hard.
I go into this because of the relationship to Purgatory; it is the proper job of Purgatory to break, to purge our attachments, so that we can enter total union with God. Lent teaches us how hard it is to do it here; that's no cake-walk coming. We all know this already, but Lent gives us something we know, a level of effort, to tell us something about what we don't know, the level of effort we haven't yet expended, but will (the usual assumptions being in place).
The thought of death places before our eyes the vanity of earthly things, the brevity of life - "all things are passing; God alone remains" - and therefore it urges us to detach ourselves from everything, to scorn every earthly satisfaction, and to seek God alone. The thought of death makes us understand that "all is vanity, except to love God and serve Him alone" (Imit. I,4) "Remember that you have only one soul; that you have only one death to die...then there will be many things about which you care nothing (T.J.), that is you, will give up everything that has no eternal value.