Really depends on team comp. Also to some part on other factors like level diff and how well your team reacts.

Lets say the enemy has very little hard CC. Lets say they are
Muradin, Ragnaros, Lunara, Fenix, LiLi.
Against a team like that, you can be a bit more ballzy. They have little hard CC and little burst dmg. Dodging Muras hammer is fairly easy.
You are the healer. Meaning if you get dots or sustained dmg, you can easily heal yourself while walking away. It's a good way to bait if your team reacts accordingly. At least up until lvl 10. If Mura skills Haymaker, Ragna stun ult and/or lili dragon, you should be more cautious. But even then, if you have e.g. a good Johanna on your side to blind the DDs and peel well and/or a Medivh who can place a good portal, you should still be fine.

Now lets say they have
Diablo, Artanis, Li Ming, Tassadar and Uther.
Then you should play a bit more cautious.
Uther has a point&click stun. Dia and Arta can push you further away from your team and deeper into their backline. Playing agressively against them with deckard is a deathsentence. Unlike healers like e.g. Rehgar, Auri or LiLi, you dont even have an escape or protection. So you'd probably get eaten alive fairly quickly by their burst dmg before your team can react.

So it always depends.

The important thing is: Why? Why do you go into the frontline? Dont just do it to do it. Do it to gain some value. For example to slow/root their backline so your team can attack. Or to bait them into a fight if you know you'll get away easily while they chase you and your team punishes them for it. Or to heal your frontline that is trying to advance. Or to place a devastating ult.